1
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Flores J, Ruscitti M, Khani S, Reilly NJ. Electronic Spectrum of α-Hydrofulvenyl Radical (C 6H 7), and a Simple and Accurate Recipe for Predicting Adiabatic Ionization Energies of Resonance-Stabilized Hydrocarbon Radicals. J Phys Chem A 2024; 128:8123-8136. [PMID: 39264134 DOI: 10.1021/acs.jpca.4c04746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
Using a combination of resonant two-photon two-color ionization (R2C2PI) and laser-induced fluorescence/dispersed fluorescence spectroscopy, we have examined the A ~ 2A″ ← X ~ 2A″ transition of the resonance-stabilized α-hydrofulvenyl radical, produced from methylcyclopentadiene dimer in a jet-cooled discharge. Like the related 1,4-pentadienyl and cyclohexadienyl radicals, the α-hydrofulvenyl Ã-state lifetime is orders of magnitude shorter than the predicted f-value implies, indicative of rapid nonradiative decay. The transition is fully allowed by symmetry but considerably weakened by transition moment interference. Intensity borrowing among a' modes brings about static (i.e., Condon) and vibronic (i.e., Herzberg-Teller) moments of similar size, the result being a spectrum substantially less origin-dominated than is usually observed for extensively delocalized radicals. Twenty A ~ -state modes and twelve X ~ -state modes are identified with high confidence and assignments for several others are suggested. In addition, from a series of two-color appearance potential scans with the A ~ -state zero-point level serving as an intermediate, we obtain a field-free adiabatic ionization energy (AIE) of 7.012(1) eV. For a set of 21 resonance-stabilized radicals bearing 5 to 11 carbon atoms, it emerges that the field-free AIE obtained by R2C2PI methods under jet-cooled conditions lies very close to the average of B3LYP/6-311G++(d,p) (with harmonic zero-point energy) and CBS-QB3 0 K calculations, with a mean absolute deviation of only 0.010(7) eV (approximately 1 kJ/mol). On average, this represents a nearly 10-fold improvement in accuracy over CBS-QB3 predictions for the same set of radicals.
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Affiliation(s)
- Jonathan Flores
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Massimo Ruscitti
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Sima Khani
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
| | - Neil J Reilly
- Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States
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2
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Khanna A, Shedge SV, Zuehlsdorff TJ, Isborn CM. Calculating absorption and fluorescence spectra for chromophores in solution with ensemble Franck-Condon methods. J Chem Phys 2024; 161:044121. [PMID: 39077907 DOI: 10.1063/5.0217080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 07/03/2024] [Indexed: 07/31/2024] Open
Abstract
Accurately modeling absorption and fluorescence spectra for molecules in solution poses a challenge due to the need to incorporate both vibronic and environmental effects, as well as the necessity of accurate excited state electronic structure calculations. Nuclear ensemble approaches capture explicit environmental effects, Franck-Condon methods capture vibronic effects, and recently introduced ensemble-Franck-Condon approaches combine the advantages of both methods. In this study, we present and analyze simulated absorption and fluorescence spectra generated with combined ensemble-Franck-Condon approaches for three chromophore-solvent systems and compare them to standard ensemble and Franck-Condon spectra, as well as to the experiment. Employing configurations obtained from ground and excited state ab initio molecular dynamics, three combined ensemble-Franck-Condon approaches are directly compared to each other to assess the accuracy and relative computational time. We find that the approach employing an average finite-temperature Franck-Condon line shape generates spectra nearly identical to the direct summation of an ensemble of Franck-Condon spectra at one-fourth of the computational cost. We analyze how the spectral simulation method, as well as the level of electronic structure theory, affects spectral line shapes and associated Stokes shifts for 7-nitrobenz-2-oxa-1,3-diazol-4-yl and Nile red in dimethyl sulfoxide and 7-methoxy coumarin-4-acetic acid in methanol. For the first time, our studies show the capability of combined ensemble-Franck-Condon methods for both absorption and fluorescence spectroscopy and provide a powerful tool for simulating linear optical spectra.
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Affiliation(s)
- Ajay Khanna
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, USA
| | - Sapana V Shedge
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, USA
| | - Tim J Zuehlsdorff
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Christine M Isborn
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, USA
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3
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Cui K, Hammes-Schiffer S. Theory for proton-coupled energy transfer. J Chem Phys 2024; 161:034113. [PMID: 39012810 DOI: 10.1063/5.0217546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Accepted: 06/06/2024] [Indexed: 07/18/2024] Open
Abstract
In the recently discovered proton-coupled energy transfer (PCEnT) mechanism, the transfer of electronic excitation energy between donor and acceptor chromophores is coupled to a proton transfer reaction. Herein, we develop a general theory for PCEnT and derive an analytical expression for the nonadiabatic PCEnT rate constant. This theory treats the transferring hydrogen nucleus quantum mechanically and describes the PCEnT process in terms of nonadiabatic transitions between reactant and product electron-proton vibronic states. The rate constant is expressed as a summation over these vibronic states, and the contribution of each pair of vibronic states depends on the square of the vibronic coupling as well as the spectral convolution integral, which can be viewed as a generalization of the Förster-type spectral overlap integral for vibronic rather than electronic states. The convolution integral also accounts for the common vibrational modes shared by the donor and acceptor chromophores for intramolecular PCEnT. We apply this theory to model systems to investigate the key features of PCEnT processes. The excited vibronic states can contribute significantly to the total PCEnT rate constant, and the common modes can either slow down or speed up the process. Because the pairs of vibronic states that contribute the most to the PCEnT rate constant may correspond to spectroscopically dark states, PCEnT could occur even when there is no apparent overlap between the donor emission and acceptor absorption spectra. This theory will assist in the interpretation of experimental data and will guide the design of additional PCEnT systems.
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Affiliation(s)
- Kai Cui
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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4
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Bashirova D, Zuehlsdorff TJ. First-Principles Modeling of the Absorption Spectrum of Crystal Violet in Solution: The Importance of Environmentally Driven Symmetry Breaking. J Phys Chem A 2024; 128:5229-5242. [PMID: 38938007 DOI: 10.1021/acs.jpca.4c00389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Theoretical spectroscopy plays a crucial role in understanding the properties of the materials and molecules. One of the most promising methods for computing optical spectra of chromophores embedded in complex environments from the first principles is the cumulant approach, where both (generally anharmonic) vibrational degrees of freedom and environmental interactions are explicitly accounted for. In this work, we verify the capabilities of the cumulant approach in describing the effect of complex environmental interactions on linear absorption spectra by studying Crystal Violet (CV) in different solvents. The experimental absorption spectrum of CV strongly depends on the nature of the solvent, indicating strong coupling to the condensed-phase environment. We demonstrate that these changes in absorption line shape are driven by an increased splitting between absorption bands of two low-lying excited states that is caused by a breaking of the D3 symmetry of the molecule and that in polar solvents, this symmetry breaking is mainly driven by electrostatic interactions with the condensed-phase environment rather than distortion of the structure of the molecule, in contrast with conclusions reached in a number of previous studies. Our results reveal the importance of explicitly including a counterion in the calculations in nonpolar solvents due to electrostatic interactions between CV and the ion. In polar solvents, these interactions are strongly reduced due to solvent screening effects, thus minimizing the symmetry breaking. Computed spectra in methanol are found to be in reasonable agreement with the experiment, demonstrating the strengths of the outlined approach in modeling strong environmental interactions.
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Affiliation(s)
- Dayana Bashirova
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Tim J Zuehlsdorff
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
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5
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Martínez-Vollbert E, Philouze C, Cavignac T, Latouche C, Loiseau F, Lanoë PH. Neutral 2-phenylbenzimidazole-based iridium(III) complexes with picolinate ancillary ligand: tuning the emission properties by manipulating the substituent on the benzimidazole ring. Dalton Trans 2024; 53:4705-4718. [PMID: 38362807 DOI: 10.1039/d3dt03498d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
We report the synthesis and characterization of ten neutral bisheteroleptic iridium(III) complexes with 2-phenylbenzimidazole cyclometallating ligand and picolinate as ancillary ligand. The 2-phenylbenzimidazole has been modified by selected substituents introduced on the cyclometallating ring and/or on the benzimidazole moiety. The integrity of the complexes has been assessed by NMR spectroscopy, by high-resolution mass spectrometry and by elemental analysis. The complexes are demonstrated to be highly phosphorescent at room temperature and a luminescence study with comprehensive ab initio calculations allow us to determine the lowest emitting excited state which depends on the substituent nature and its position on the cyclometallating ligand.
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Affiliation(s)
| | | | - Théo Cavignac
- Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel, IMN, F-44000 Nantes, France.
| | - Camille Latouche
- Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel, IMN, F-44000 Nantes, France.
- Insitut universitaire de France (IUF), France
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6
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Palmer MH, Hoffmann SV, Jones NC, Coreno M, de Simone M, Grazioli C, Aitken RA, Perrault L, Patterson ILJ. The ultraviolet and vacuum ultraviolet absorption spectrum of gamma-pyrone; the singlet states studied by configuration interaction and density functional calculations. J Chem Phys 2024; 160:054305. [PMID: 38341687 DOI: 10.1063/5.0186919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/05/2024] [Indexed: 02/13/2024] Open
Abstract
A synchrotron based vacuum ultraviolet absorption spectrum for γ-pyrone has been interpreted in terms of singlet excited electronic states using a variety of coupled cluster, configuration interaction, and density functional calculations. The extremely weak spectral onset at 3.557 eV shows eight vibrational peaks, which following previous analyses, are attributed to a forbidden 1A2 state. A contrasting broad peak with a maximum at 5.381 eV has a relatively high cross-section of 30 Mb; this arises from three overlapping states, where a 1A1 state dominates over progressively weaker 1B2 and 1B1 states. After fitting the second band to a polynomial Gaussian function and plotting the regular residuals over 20 vibrational peaks, we have had limited success in analyzing this fine structure. However, the small separation between these three states clearly shows that their vibrational satellites must overlap. Singlet valence and Rydberg state vibrational profiles were determined by configuration interaction using the CAM-B3LYP density functional. Vibrational analysis using both the Franck-Condon and Herzberg-Teller procedures showed that both procedures contributed to the profiles. Theoretical Rydberg states were evaluated by a highly focused CI procedure. The superposition of the lowest photoelectron spectral band on the vacuum ultraviolet spectrum near 6.4 eV shows that the 3s and 3p Rydberg states based on the 2B2 ionic state are present; those based on the other low-lying ionic state (X2B1) are destroyed by broadening; this is a dramatic extension of the broadening previously witnessed in our studies of halogenobenzenes.
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Affiliation(s)
- Michael H Palmer
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ Scotland, United Kingdom
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Nykola C Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Marcello Coreno
- ISM-CNR, Instituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
| | - Monica de Simone
- IOM-CNR, Istituto Officina dei Materiali, Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - Cesare Grazioli
- IOM-CNR, Istituto Officina dei Materiali, Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - R Alan Aitken
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST Scotland, United Kingdom
| | - Loëlia Perrault
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST Scotland, United Kingdom
| | - Iain L J Patterson
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST Scotland, United Kingdom
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7
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Roy A, Samanta S, Ray S, S SK, Mondal P. Unraveling the mystery of solvation-dependent fluorescence of fluorescein dianion using computational study. J Chem Phys 2024; 160:034302. [PMID: 38235793 DOI: 10.1063/5.0180218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 12/18/2023] [Indexed: 01/19/2024] Open
Abstract
Fluorescein, one of the brightest fluorescent dye molecules, is a widely used fluorophore for various applications from biomedicine to industry. The dianionic form of fluorescein is responsible for its high fluorescence quantum yield. Interestingly, the molecule was found to be nonfluorescent in the gas phase. This characteristic is attributed to the photodetachment process, which out-competes the fluorescence emission in the gas phase. In this work, we show that the calculated vertical and adiabatic detachment energies of fluorescein dianion in the gas and solvent phases account for the drastic differences observed in their fluorescence characteristics. The functional dependence of these detachment energies on the dianion's microsolvation was systematically investigated. The performance of different solvent models was also assessed. The higher thermodynamic stability of fluorescein dianion over the monoanion doublet in the solvent phase plays a crucial role in quenching photodetachment and activating the radiative channel with a high fluorescence quantum yield.
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Affiliation(s)
- Abheek Roy
- Department of Physics and Center for Atomic, Molecular, and Optical Sciences and Technologies (CAMOST), Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Suvadip Samanta
- Department of Chemistry and Center for Atomic, Molecular, and Optical Sciences and Technologies (CAMOST), Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Soumyadip Ray
- Department of Chemistry and Center for Atomic, Molecular, and Optical Sciences and Technologies (CAMOST), Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Sunil Kumar S
- Department of Physics and Center for Atomic, Molecular, and Optical Sciences and Technologies (CAMOST), Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Padmabati Mondal
- Department of Chemistry and Center for Atomic, Molecular, and Optical Sciences and Technologies (CAMOST), Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
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8
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Guo T, Xu J, Chen Y, Ma S, Zhang Y. Ab initio calculations on the X∼ 2B 1 → X∼ 1A 1 photoelectron spectrum of thioformaldehyde negative ion. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 304:123390. [PMID: 37708756 DOI: 10.1016/j.saa.2023.123390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/27/2023] [Accepted: 09/08/2023] [Indexed: 09/16/2023]
Abstract
The equilibrium structures, multidimensional potential energy surfaces, and anharmonic vibrational frequencies of thioformaldehyde (H2CS) and its 2B1 radical anion were obtained at the (U)CCSD(T)-F12a/cc-pVTZ-F12 level; and the photoelectron spectrum of H2CS-X∼2B1→ H2CS X∼1A1 was simulated by calculating the Franck-Condon factors (FCFs). The additional electrons cause a significant change in the bond length of the C = S bond of H2CS, which affects the potential energy surface and the C = S bond stretching mode, while the interaction between electrons turns the originally planar structure of H2CS into a slightly out-of-plane umbrella structure, resulting in an unusual change in the vibrational frequency of the out-of-plane bending mode. Finally, a time-independent eigenstate-free Raman wave function approach (RWF) was used to calculate the photoelectron spectrum of H2CS and to point out the changes in the band under the influence of different temperatures. These data provides a theoretical basis for interstellar observations and experimental studies.
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Affiliation(s)
- Tian Guo
- School of Science, Xi'an University of Posts and Telecommunications, Xi'an 710121, China
| | - Jiangang Xu
- School of Science, Xi'an University of Posts and Telecommunications, Xi'an 710121, China
| | - Yannan Chen
- School of Science, Xi'an University of Posts and Telecommunications, Xi'an 710121, China
| | - Shuangxiong Ma
- School of Science, Xi'an University of Posts and Telecommunications, Xi'an 710121, China
| | - Yunguang Zhang
- School of Science, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
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9
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Wenzel M, Mitric R. Prediction of fluorescence quantum yields using the extended thawed Gaussian approximation. J Chem Phys 2023; 159:234113. [PMID: 38108487 DOI: 10.1063/5.0178106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/26/2023] [Indexed: 12/19/2023] Open
Abstract
Spontaneous emission and internal conversion rates are calculated within harmonic approximations and compared to the results obtained within the semi-classical extended thawed Gaussian approximation (ETGA). This is the first application of the ETGA in the calculation of internal conversion and emission rates for real molecular systems, namely, formaldehyde, fluorobenzene, azulene, and a dicyano-squaraine dye. The viability of the models as black-box tools for prediction of spontaneous emission and internal conversion rates is assessed. All calculations were done using a consistent protocol in order to investigate how different methods perform without previous experimental knowledge using density functional theory (DFT) and time-dependent DFT (TD-DFT) with B3LYP, PBE0, ωB97XD, and CAM-B3LYP functionals. Contrasting the results with experimental data shows that there are further improvements required before theoretical predictions of emission and internal conversion rates can be used as reliable indicators for the photo-luminescence properties of molecules. We find that the ETGA performs rather similar to the vertical harmonical model. Including anharmonicities in the calculation of internal conversion rates has a moderate effect on the quantitative results in the studied systems. The emission rates are fairly stable with respect to computational parameters, but the internal conversion rate reveals itself to be highly dependent on the choice of the spectral line shape function, particularly the width of the Lorentzian function, associated with homogeneous broadening.
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Affiliation(s)
- Michael Wenzel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer Str. 42, 97074 Würzburg, Germany
| | - Roland Mitric
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer Str. 42, 97074 Würzburg, Germany
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10
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Chang JL, Chen HY, Huang YJ. Reassignment of the Photoelectron Spectrum of Methylketene Using a Hybrid Model of Harmonic and Anharmonic Oscillators to Compute Franck-Condon Factors. ACS OMEGA 2023; 8:40685-40694. [PMID: 37953835 PMCID: PMC10637627 DOI: 10.1021/acsomega.3c05750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/02/2023] [Indexed: 11/14/2023]
Abstract
We constructed a hybrid model of harmonic and anharmonic oscillators to compute Franck-Condon factors and interpret the photoelectron spectrum of methylketene. The equilibrium structures of methylketene and its cation were optimized, and then, the harmonic and anharmonic vibrational frequencies were computed using the B3LYP, PBE0, APFD, and ωB97XD approaches of the density functional theory. The photoelectron spectrum of methylketene was simulated by computing the Franck-Condon factors with both the harmonic and hybrid models. The adiabatic ionization energy of methylketene was computed by using the CCSD(T) approach extrapolating to the complete basis set limit. The simulated photoelectron spectra are consistent with those from the experiment for both the harmonic and hybrid models. However, the error in band positions is reduced by using the hybrid model. The computed adiabatic ionization energies of methylketene are in agreement with the experiment, with the smallest error being 0.017 eV. Our interpretation based on the theoretical spectrum led to the reassignment of the experimental photoelectron spectrum of methylketene.
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Affiliation(s)
- Jia-Lin Chang
- Department of Science Education
and Application, National Taichung University
of Education, Taichung 403514, Taiwan,
Republic of China
| | - Hsiang-Yu Chen
- Department of Science Education
and Application, National Taichung University
of Education, Taichung 403514, Taiwan,
Republic of China
| | - Yun-Jhu Huang
- Department of Science Education
and Application, National Taichung University
of Education, Taichung 403514, Taiwan,
Republic of China
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11
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Palmer MH, Hoffmann SV, Jones NC, Coreno M, de Simone M, Grazioli C, Aitken RA, Peureux C. High-level studies of the singlet states of quadricyclane, including analysis of a new experimental vacuum ultraviolet absorption spectrum by configuration interaction and density functional calculations. J Chem Phys 2023; 158:234303. [PMID: 37318170 DOI: 10.1063/5.0151758] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/30/2023] [Indexed: 06/16/2023] Open
Abstract
A synchrotron-based vacuum ultraviolet absorption spectrum (VUV) of quadricyclane (QC) is reported with energies up to 10.8 eV. Extensive vibrational structure has been extracted from the broad maxima by fitting short energy ranges of the VUV spectrum to high level polynomial functions and processing the regular residuals. Comparison of these data with our recent high-resolution photoelectron spectral of QC showed that this structure must be attributed to Rydberg states (RS). Several of these appear before the valence states at higher energies. Both types of states have been calculated by configuration interaction, including symmetry-adapted cluster studies (SAC-CI) and time dependent density functional theoretical methods (TDDFT). There is a close correlation between the SAC-CI vertical excitation energies (VEE) and both Becke 3-parameter hybrid functional (B3LYP), especially Coulomb-attenuating method-B3LYP determined ones. The VEE for several low-lying s-, p, d-, and f-RS have been determined by SAC-CI and adiabatic excitation energies by TDDFT methods. Searches for equilibrium structures for 11,3A2 and 11B1 states for QC led to rearrangement to a norbornadiene structure. Determination of the experimental 00 band positions, which show extremely low cross-sections, has been assisted by matching features in the spectra with Franck-Condon (FC) fits. Herzberg-Teller (HT) vibrational profiles for the RS are more intense than the FC ones, but only at high energy, and are attributed to up to ten quanta. The vibrational fine structure of the RS calculated by both FC and HT procedures gives an easy route to generating HT profiles for ionic states, which usually require non-standard procedures.
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Affiliation(s)
- Michael H Palmer
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Nykola C Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Marcello Coreno
- ISM-CNR, Istituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
| | - Monica de Simone
- IOM-CNR, Istituto Officina dei Materiali, Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - Cesare Grazioli
- IOM-CNR, Istituto Officina dei Materiali, Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - R Alan Aitken
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland, United Kingdom
| | - Coralyse Peureux
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland, United Kingdom
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12
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Solaris J, Krueger TD, Chen C, Fang C. Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red. Molecules 2023; 28:3506. [PMID: 37110741 PMCID: PMC10144053 DOI: 10.3390/molecules28083506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Proton transfer processes of organic molecules are key to charge transport and photoprotection in biological systems. Among them, excited-state intramolecular proton transfer (ESIPT) reactions are characterized by quick and efficient charge transfer within a molecule, resulting in ultrafast proton motions. The ESIPT-facilitated interconversion between two tautomers (PS and PA) comprising the tree fungal pigment Draconin Red in solution was investigated using a combination of targeted femtosecond transient absorption (fs-TA) and excited-state femtosecond stimulated Raman spectroscopy (ES-FSRS) measurements. Transient intensity (population and polarizability) and frequency (structural and cooling) dynamics of -COH rocking and -C=C, -C=O stretching modes following directed stimulation of each tautomer elucidate the excitation-dependent relaxation pathways, particularly the bidirectional ESIPT progression out of the Franck-Condon region to the lower-lying excited state, of the intrinsically heterogeneous chromophore in dichloromethane solvent. A characteristic overall excited-state PS-to-PA transition on the picosecond timescale leads to a unique "W"-shaped excited-state Raman intensity pattern due to dynamic resonance enhancement with the Raman pump-probe pulse pair. The ability to utilize quantum mechanics calculations in conjunction with steady-state electronic absorption and emission spectra to induce disparate excited-state populations in an inhomogeneous mixture of similar tautomers has broad implications for the modeling of potential energy surfaces and delineation of reaction mechanisms in naturally occurring chromophores. Such fundamental insights afforded by in-depth analysis of ultrafast spectroscopic datasets are also beneficial for future development of sustainable materials and optoelectronics.
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13
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Tikhonov SA, Sidorin AE, Ksenofontov AA, Kosyanov DY, Samoilov IS, Skitnevskaya AD, Trofimov AB, Antina EV, Berezin MB, Vovna VI. XPS and quantum chemical analysis of 4Me-BODIPY derivatives. Phys Chem Chem Phys 2023; 25:5211-5225. [PMID: 36723097 DOI: 10.1039/d2cp04541a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The results of a X-ray photoelectron spectroscopy (XPS) and steady-state absorption spectroscopy study of the electronic structure, and cationic and excited states of a series of 1,3,5,7-tetramethyl-substituted BODIPYs (4Me,2R-BODIPYs) are presented. The experimental data were interpreted using high-level ab initio quantum chemical computations, including the algebraic diagrammatic construction method for the polarization propagator of the second order (ADC(2)), the outer-valence Green's function (OVGF) method, the density functional (DFT) approach, and the time-dependent DFT (TD-DFT) approach. Substitution effects on the XPS and absorption spectra were determined for 2,6-positions of 4Me,2R-BODIPY pyrrole nuclei (R = H, Br, Bu, benzyl). A very satisfactory performance of the DFT Koopmans theorem analogue was demonstrated with respect to the energy intervals between the electronic levels of 4Me,2R-BODIPY above 13 eV (BHHLYP functional) and the values of the HOMO-LUMO energy gap (ωB97X functional).
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Affiliation(s)
- Sergey A Tikhonov
- Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences, Piip blvd. 9, 683023 Petropavlovsk-Kamchatsky, Russian Federation.
| | - Andrey E Sidorin
- Far Eastern Federal University, 10 Ajax Bay, Russky Island, 690922 Vladivostok, Russian Federation
| | - Alexander A Ksenofontov
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya Str. 1, 153045 Ivanovo, Russian Federation
| | - Denis Yu Kosyanov
- Far Eastern Federal University, 10 Ajax Bay, Russky Island, 690922 Vladivostok, Russian Federation.,Institute of Automation and Control Processes, Far Eastern Branch, Russian Academy of Sciences, 5 Radio Street, 690041 Vladivostok, Russian Federation
| | - Ilya S Samoilov
- Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences, Piip blvd. 9, 683023 Petropavlovsk-Kamchatsky, Russian Federation. .,Department of Photonics, Saint Petersburg State University, 7-9 Universitetskaya Embankment, 199034 St. Petersburg, Russian Federation
| | - Anna D Skitnevskaya
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russian Federation
| | - Alexander B Trofimov
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russian Federation.,Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation
| | - Elena V Antina
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya Str. 1, 153045 Ivanovo, Russian Federation
| | - Mikhail B Berezin
- G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Akademicheskaya Str. 1, 153045 Ivanovo, Russian Federation
| | - Vitaliy I Vovna
- Far Eastern Federal University, 10 Ajax Bay, Russky Island, 690922 Vladivostok, Russian Federation
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14
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Cerezo J, Santoro F. FCclasses3: Vibrationally-resolved spectra simulated at the edge of the harmonic approximation. J Comput Chem 2023; 44:626-643. [PMID: 36380723 PMCID: PMC10100349 DOI: 10.1002/jcc.27027] [Citation(s) in RCA: 38] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/03/2022] [Accepted: 10/16/2022] [Indexed: 11/17/2022]
Abstract
We introduce FCclasses3, a code to carry out vibronic simulations of electronic spectra and nonradiative rates, based on the harmonic approximation. Key new features are: implementation of the full family of vertical and adiabatic harmonic models, vibrational analysis in curvilinear coordinates, extension to several electronic spectroscopies and implementation of time-dependent approaches. The use of curvilinear valence internal coordinates allows the adoption of quadratic model potential energy surfaces (PES) of the initial and final states expanded at arbitrary configurations. Moreover, the implementation of suitable projectors provides a robust framework for defining reduced-dimensionality models by sorting flexible coordinates out of the harmonic subset, so that they can then be treated at anharmonic level, or with mixed quantum classical approaches. A set of tools to facilitate input preparation and output analysis is also provided. We show the program at work in the simulation of different spectra (one and two-photon absorption, emission and resonance Raman) and internal conversion rate of a typical rigid molecule, anthracene. Then, we focus on absorption and emission spectra of a series of flexible polyphenyl molecules, highlighting the relevance of some of the newly implemented features. The code is freely available at http://www.iccom.cnr.it/en/fcclasses/.
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Affiliation(s)
- Javier Cerezo
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem)Universidad Autónoma de MadridMadridSpain
- Consiglio Nazionale delle RicercheIstituto di Chimica dei Composti Organo Metallici (ICCOM‐CNR)PisaItaly
| | - Fabrizio Santoro
- Consiglio Nazionale delle RicercheIstituto di Chimica dei Composti Organo Metallici (ICCOM‐CNR)PisaItaly
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15
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Wenzel M, Mitric R. Internal conversion rates from the extended thawed Gaussian approximation: Theory and validation. J Chem Phys 2023; 158:034105. [PMID: 36681643 DOI: 10.1063/5.0130340] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The theoretical prediction of the rates of nonradiative processes in molecules is fundamental in assessing their emissive properties. In this context, global harmonic models have been widely used to simulate vibronic spectra as well as internal conversion rates and to predict photoluminescence quantum yields. However, these simplified models suffer from the limitations that are inherent to the harmonic approximation and can have a severe effect on the calculated internal conversion rates. Therefore, the development of more accurate semiclassical methods is highly desirable. Here, we introduce a procedure for the calculation of nonradiative rates in the framework of the time-dependent semi-classical Extended Thawed Gaussian Approximation (ETGA). We systematically investigate the performance of the ETGA method by comparing it to the adiabatic and vertical harmonic methods, which belong to the class of widely used global harmonic models. Its performance is tested in potentials that cannot be treated adequately by global harmonic models, beginning with Morse potentials of varying anharmonicity followed by a double well potential. The calculated radiative and nonradiative internal conversion rates are compared to reference values based on exact quantum dynamics. We find that the ETGA has the capability to predict internal conversion rates in anharmonic systems with an appreciable energy gap, whereas the global harmonic models prove to be insufficient.
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Affiliation(s)
- Michael Wenzel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer Str. 42, 97074 Würzburg, Germany
| | - Roland Mitric
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer Str. 42, 97074 Würzburg, Germany
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16
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Palmer MH, Coreno M, de Simone M, Grazioli C, Jones NC, Hoffmann SV, Aitken RA, Sonecha DK. The ionic and ground states of gamma-pyrone. The photoionization spectrum studied by synchrotron radiation and interpreted by configuration interaction and density functional calculations. J Chem Phys 2023; 158:014304. [PMID: 36610975 DOI: 10.1063/5.0128764] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A synchrotron-based photoionization spectrum up to 27 eV represents a considerable improvement in resolution over early He(I) and He(II) spectra. Symmetry-adapted coupled cluster calculations of the ionic state sequence give the sequence of state vertical ionization energies (VIE) as 12B2 < 12B1 < 12A2 < 22B1 < 12A1. Generally, these symmetry-adapted cluster configuration interactions VIE match reasonably well with the experimental spectrum over this wide energy range. Density functional calculations of the corresponding adiabatic terms (AIE) were also performed. Higher energy ionic states were determined by complete active space self-consistent field methods; these include all π-ionizations and some σ-ionic states. These were analyzed by Franck-Condon (FC) procedures and compared with an experiment. The spectral onset is complex, where two states, later shown to be the 12B2 and 12B1 states, are strongly overlapping. The superposition of the FC vibrational structure in the 12B2 and 12B1 states accounts for most of the peaks arising at the onset of the photoelectron spectra. However, the small separation between these two ionic states makes vibronic interaction fairly inevitable. In the absence of Herzberg-Teller analyses for ionic states, we have sought and determined a transition state between the 12B2 and 12B1 states, showing that vibronic coupling does occur. The lack of degradation in the vibrational envelope of the higher of the two states contrasts with our previous work on the halogenobenzenes, where overlapping state envelopes led to considerable widening of the line width at half-height of the higher energy states.
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Affiliation(s)
- Michael H Palmer
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Marcello Coreno
- ISM-CNR, Instituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
| | - Monica de Simone
- IOM-CNR, Istituto Officina dei Materiali, Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - Cesare Grazioli
- IOM-CNR, Istituto Officina dei Materiali, Basovizza SS-14, Km 163.5, 34149 Trieste, Italy
| | - Nykola C Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK, 8000 Aarhus C, Denmark
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK, 8000 Aarhus C, Denmark
| | - R Alan Aitken
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, Scotland, United Kingdom
| | - Dheirya K Sonecha
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, Scotland, United Kingdom
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17
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Excitation of phenanthridines in aqueous solution: Comparative theoretical analysis. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Chih YR, Lin YT, Yin CW, Chen YJ. High Intrinsic Phosphorescence Efficiency and Density Functional Theory Modeling of Ru(II)-Bipyridine Complexes with π-Aromatic-Rich Cyclometalated Ligands: Attributions of Spin-Orbit Coupling Perturbation and Efficient Configurational Mixing of Singlet Excited States. ACS OMEGA 2022; 7:48583-48599. [PMID: 36591186 PMCID: PMC9798779 DOI: 10.1021/acsomega.2c07276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
A series of π-aromatic-rich cyclometalated ruthenium(II)-(2,2'-bipyridine) complexes ([Ru(bpy)2(πAr-CM)]+) in which πAr-CM is diphenylpyrazine or 1-phenylisoquinoline were prepared. The [Ru(bpy)2(πAr-CM)]+ complexes had remarkably high phosphorescence rate constants, k RAD(p), and the intrinsic phosphorescence efficiencies (ιem(p) = k RAD(p)/(νem(p))3) of these complexes were found to be twice the magnitudes of simply constructed cyclometalated ruthenium(II) complexes ([Ru(bpy)2(sc-CM)]+), where νem(p) is the phosphorescence frequency and sc-CM is 2-phenylpyridine, benzo[h]quinoline, or 2-phenylpyrimidine. Density functional theory (DFT) modeling of the [Ru(bpy)2(CM)]+ complexes indicated numerous singlet metal-to-ligand charge transfers for 1MLCT-(Ru-bpy) and 1MLCT-(Ru-CM), excited states in the low-energy absorption band and 1ππ*-(aromatic ligand) (1ππ*-LAr) excited states in the high-energy band. DFT modeling of these complexes also indicated phosphorescence-emitting state (Te) configurations with primary MLCT-(Ru-bpy) characteristics. The variation in ιem(p) for the spin-forbidden Te (3MLCT-(Ru-bpy)) excited state of the complex system that was examined in this study can be understood through the spin-orbit coupling (SOC)-mediated sum of intensity stealing (∑SOCM-IS) contribution from the primary intensity of the low-energy 1MLCT states and second-order intensity perturbation from the significant configuration between the low-energy 1MLCT and high-energy intense 1ππ*-LAr states. In addition, the observation of unusually high ιem(p) magnitudes for these [Ru(bpy)2(πAr-CM)]+ complexes can be attributed to the values for both intensity factors in the ∑SOCM-IS formalism being individually greater than those for [Ru(bpy)2(sc-CM)]+ ions.
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Affiliation(s)
| | | | | | - Yuan Jang Chen
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, R.O.C.
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19
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Garcia AD, Topin J, Bocková J, Jones NC, Hoffmann SV, Meinert C. Chiroptical activity of gas-phase propylene oxide predicting the handedness of interstellar circular polarization in the presolar nebula. SCIENCE ADVANCES 2022; 8:eadd4614. [PMID: 36399555 PMCID: PMC9674286 DOI: 10.1126/sciadv.add4614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Propylene oxide, the first chiral molecule recently detected in the interstellar medium, has once again raised the question whether biomolecular chirality might have cosmic origins. However, accurate chiroptical properties of propylene oxide in the ultraviolet spectral range necessary to suggest possible asymmetric synthetic routes in the gas phase are scarce. Here, we report on the first experimental measurements of the anisotropy spectra of gas-phase propylene oxide in the vacuum ultraviolet spectral range. Our experimental results provide novel insights into the handedness of interstellar circular polarization at the dawn of molecular evolution of our star- and planet-forming region. Besides the fundamental importance of this new investigation for understanding the origin and evolution of homochirality on Earth, our high-resolution experimental electronic circular dichroism data will inspire new efforts in quantum computational spectroscopy.
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Affiliation(s)
- Adrien D. Garcia
- Institut de Chimie de Nice, Université Côte d’Azur, UMR 7272 CNRS, Nice 06108, France
| | - Jérémie Topin
- Institut de Chimie de Nice, Université Côte d’Azur, UMR 7272 CNRS, Nice 06108, France
| | - Jana Bocková
- Institut de Chimie de Nice, Université Côte d’Azur, UMR 7272 CNRS, Nice 06108, France
| | - Nykola C. Jones
- ISA, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus, Denmark
| | - Søren V. Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus, Denmark
| | - Cornelia Meinert
- Institut de Chimie de Nice, Université Côte d’Azur, UMR 7272 CNRS, Nice 06108, France
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20
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Falbo E, Fusè M, Lazzari F, Mancini G, Barone V. Integration of Quantum Chemistry, Statistical Mechanics, and Artificial Intelligence for Computational Spectroscopy: The UV-Vis Spectrum of TEMPO Radical in Different Solvents. J Chem Theory Comput 2022; 18:6203-6216. [PMID: 36166322 PMCID: PMC9558374 DOI: 10.1021/acs.jctc.2c00654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Indexed: 11/30/2022]
Abstract
The ongoing integration of quantum chemistry, statistical mechanics, and artificial intelligence is paving the route toward more effective and accurate strategies for the investigation of the spectroscopic properties of medium-to-large size chromophores in condensed phases. In this context we are developing a novel workflow aimed at improving the generality, reliability, and ease of use of the available computational tools. In this paper we report our latest developments with specific reference to unsupervised atomistic simulations employing non periodic boundary conditions (NPBC) followed by clustering of the trajectories employing optimized feature spaces. Next accurate variational computations are performed for a representative point of each cluster, whereas intracluster fluctuations are taken into account by a cheap yet reliable perturbative approach. A number of methodological improvements have been introduced including, e.g., more realistic reaction field effects at the outer boundary of the simulation sphere, automatic definition of the feature space by continuous perception of solute-solvent interactions, full account of polarization and charge transfer in the first solvation shell, and inclusion of vibronic contributions. After its validation, this new approach has been applied to the challenging case of solvatochromic effects on the UV-vis spectra of a prototypical nitroxide radical (TEMPO) in different solvents. The reliability, effectiveness, and robustness of the new platform is demonstrated by the remarkable agreement with experiment of the results obtained through an unsupervised approach characterized by a strongly reduced computational cost as compared to that of conventional quantum mechanics and molecular mechanics models without any accuracy reduction.
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Affiliation(s)
- Emanuele Falbo
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Marco Fusè
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
- Dipartimento
di Medicina Molecolare e Traslazionale, Università di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Federico Lazzari
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Giordano Mancini
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Vincenzo Barone
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
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21
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Wang J, Liu Y. Vibrationally resolved absorption and fluorescence spectra of flavins: A theoretical simulation in the gas phase. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jinyu Wang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry Beijing Normal University Beijing China
| | - Ya‐Jun Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry Beijing Normal University Beijing China
- Center for Advanced Materials Research Beijing Normal University Zhuhai China
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22
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Bourgalais J, Carstensen HH, Herbinet O, Garcia GA, Arnoux P, Tran LS, Vanhove G, Nahon L, Hochlaf M, Battin-Leclerc F. Product Identification in the Low-Temperature Oxidation of Cyclohexane Using a Jet-Stirred Reactor in Combination with SVUV-PEPICO Analysis and Theoretical Quantum Calculations. J Phys Chem A 2022; 126:5784-5799. [PMID: 35998573 DOI: 10.1021/acs.jpca.2c04490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclohexane oxidation chemistry was investigated using a near-atmospheric pressure jet-stirred reactor at T = 570 K and equivalence ratio ϕ = 0.8. Numerous intermediates including hydroperoxides and highly oxygenated molecules were detected using synchrotron vacuum ultraviolet photoelectron photoion coincidence spectroscopy. Supported by high-level quantum calculations, the analysis of photoelectron spectra allowed the firm identification of molecular species formed during the oxidation of cyclohexane. Besides, this work validates recently published gas chromatography and synchrotron vacuum ultraviolet photoionization mass spectrometry data. Unambiguous detection of characteristic hydroperoxides (e.g., γ-ketohydroperoxides) and their respective decomposition products provides support for the conventional O2 addition channels up to the third addition and their relative contribution to the cyclohexane oxidation. The results were also compared with the predictions of a recently proposed new detailed kinetic model of cyclohexane oxidation. Most of the predictions are in line with the current experimental findings, highlighting the robustness of the kinetic model. However, the analysis of the recorded slow photoelectron spectra indicating the possible presence of C5 species in the kinetic model provides hints that the substituted cyclopentyl radicals from cyclohexyl ring opening might play a minor role in cyclohexane oxidation. Potentially important missing reactions are also discussed.
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Affiliation(s)
| | - Hans-Heinrich Carstensen
- Thermochemical Processes Group (GPT), Department of Chemical and Environmental Engineering, Engineering and Architecture School, University of Zaragoza, C. Maria de Luna, 50018 Zaragoza, Spain.,Fundacion Agencia Aragonesa para la Investigacion y el Desarrollo (ARAID), Av. de Ranillas, 50018 Zagaroza, Spain
| | | | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | | | - Luc-Sy Tran
- Université Lille, CNRS, UMR 8522─PC2A─Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Guillaume Vanhove
- Université Lille, CNRS, UMR 8522─PC2A─Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes, F-77454 Champs-sur-Marne, France
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23
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Martìnez-Vollbert E, Ciambrone C, Lafargue-Dit-Hauret W, Latouche C, Loiseau F, Lanoë PH. Bis-Heteroleptic Cationic Iridium(III) Complexes Featuring Cyclometalating 2-Phenylbenzimidazole Ligands: A Combined Experimental and Theoretical Study. Inorg Chem 2022; 61:3033-3049. [PMID: 35143722 DOI: 10.1021/acs.inorgchem.1c02968] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this report, we investigate a new family of cationic iridium(III) complexes featuring the cyclometalating ligand 2-phenylbenzimidazole and ancillary ligand 4,4'-dimethyl-2,2'-bipyridine. Our benchmark complex IrL12 (L1 = 2-phenylbenzimidazole) displays emission properties similar to those of the archetypical complex 2,2'-dipyridylbis(2',4'-phenylpyridine)iridium(III) in deaerated CH3CN (Φ = 0.20, λem = 584 nm and Φ = 0.14, λem = 585 nm, respectively) but exhibits a higher photoluminescence quantum yield in deaerated CH2Cl2 (Φ = 0.32, λem = 566 nm and Φ = 0.20, λem = 595 nm, respectively) and especially a lower nonradiative constant (knr = 6.6 × 105 s-1 vs knr = 1.4 × 106 s-1, respectively). As a primary investigation, we explored the influence of the introduction of electron-donating and electron-withdrawing groups on the benzimidazole moiety and the synergetic effect of the substitution of the cyclometalating phenyl moiety at the para position with the same substituents. The emission energy displays very good correlation with the Hammett constants of the introduced substituents as well as with ΔEredox values, which allow us to ascribe the phosphorescence of these series to emanate mainly from a mixed metal/ligand to ligand charge transfer triplet excited state (3M/LLCT*). Two complexes (IrL52 and IrL82) display a switch of the lowest triplet excited state from 3M/LLCT* to ligand centered (3LC*), from the less polar CH2Cl2 to the more polar CH3CN. The observed results are supported by (TD)-DFT computations considering the vibrational contributions to the electronic transitions. Chromaticity diagrams based on the maximum emission wavelength of the recorded and simulated phosphorescence spectra demonstrate the strong promise of our complexes as emitting materials, together with the very good agreement between experimental and theoretical results.
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Affiliation(s)
| | | | | | - Camille Latouche
- Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel, IMN, F-44000 Nantes, France
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24
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Montorsi F, Segatta F, Nenov A, Mukamel S, Garavelli M. Soft X-ray Spectroscopy Simulations with Multiconfigurational Wave Function Theory: Spectrum Completeness, Sub-eV Accuracy, and Quantitative Reproduction of Line Shapes. J Chem Theory Comput 2022; 18:1003-1016. [PMID: 35073066 PMCID: PMC8830047 DOI: 10.1021/acs.jctc.1c00566] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Indexed: 01/04/2023]
Abstract
Multireference methods are known for their ability to accurately treat states of very different nature in many molecular systems, facilitating high-quality simulations of a large variety of spectroscopic techniques. Here, we couple the multiconfigurational restricted active space self-consistent field RASSCF/RASPT2 method (of the CASSCF/CASPT2 methods family) to the displaced harmonic oscillator (DHO) model, to simulate soft X-ray spectroscopy. We applied such an RASSCF/RASPT2+DHO approach at the K-edges of various second-row elements for a set of small organic molecules that have been recently investigated at other levels of theory. X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopy (XPS) are simulated with a sub-eV accuracy and a correct description of the spectral line shapes. The method is extremely sensitive to the observed spectral shifts on a series of differently fluorinated ethylene systems, provides spectral fingerprints to distinguish between stable conformers of the glycine molecule, and accurately captures the vibrationally resolved carbon K-edge spectrum of formaldehyde. Differences with other theoretical methods are demonstrated, which show the advantages of employing a multireference/multiconfigurational approach. A protocol to systematically increase the number of core-excited states considered while maintaining a contained computational cost is presented. Insight is eventually provided for the effects caused by removing core-electrons from a given atom in terms of bond rearrangement and influence on the resulting spectral shapes within a unitary orbital-based framework for both XPS and XANES spectra.
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Affiliation(s)
- Francesco Montorsi
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Francesco Segatta
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Artur Nenov
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Shaul Mukamel
- Department
of Chemistry and Department of Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Marco Garavelli
- Department
of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale del Risorgimento, 4, 40136 Bologna, Italy
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25
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Palmer MH, Coreno M, de Simone M, Grazioli C, Jones NC, Hoffmann SV, Aitken RA. The ground and ionized states of azulene; a combined study of the vibrational energy levels by photoionization, configuration interaction and density functional calculations. J Chem Phys 2022; 156:064305. [DOI: 10.1063/5.0073505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | | | | | - Cesare Grazioli
- IOM-CNR, TASC Laboratory, Consiglio Nazionale delle Ricerche Istituto di Struttura della Materia, Italy
| | - Nykola C. Jones
- Aarhus University Department of Physics and Astronomy, Denmark
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26
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Prlj A, Marsili E, Hutton L, Hollas D, Shchepanovska D, Glowacki DR, Slavíček P, Curchod BFE. Calculating Photoabsorption Cross-Sections for Atmospheric Volatile Organic Compounds. ACS EARTH & SPACE CHEMISTRY 2022; 6:207-217. [PMID: 35087992 PMCID: PMC8785186 DOI: 10.1021/acsearthspacechem.1c00355] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/25/2021] [Accepted: 12/03/2021] [Indexed: 05/30/2023]
Abstract
Characterizing the photochemical reactivity of transient volatile organic compounds (VOCs) in our atmosphere begins with a proper understanding of their abilities to absorb sunlight. Unfortunately, the photoabsorption cross-sections for a large number of transient VOCs remain unavailable experimentally due to their short lifetime or high reactivity. While structure-activity relationships (SARs) have been successfully employed to estimate the unknown photoabsorption cross-sections of VOCs, computational photochemistry offers another promising strategy to predict not only the vertical electronic transitions of a given molecule but also the width and shape of the bands forming its absorption spectrum. In this work, we focus on the use of the nuclear ensemble approach (NEA) to determine the photoabsorption cross-section of four exemplary VOCs, namely, acrolein, methylhydroperoxide, 2-hydroperoxy-propanal, and (microsolvated) pyruvic acid. More specifically, we analyze the influence that different strategies for sampling the ground-state nuclear density-Wigner sampling and ab initio molecular dynamics with a quantum thermostat-can have on the simulated absorption spectra. We highlight the potential shortcomings of using uncoupled harmonic modes within Wigner sampling of nuclear density to describe flexible or microsolvated VOCs and some limitations of SARs for multichromophoric VOCs. Our results suggest that the NEA could constitute a powerful tool for the atmospheric community to predict the photoabsorption cross-section for transient VOCs.
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Affiliation(s)
- Antonio Prlj
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Emanuele Marsili
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Lewis Hutton
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
| | - Daniel Hollas
- Department
of Chemistry, Durham University, Durham DH1 3LE, U.K.
- Department
of Physical Chemistry, University of Chemistry
and Technology, Prague, Technická 5, Prague 16628, Czech Republic
| | - Darya Shchepanovska
- Centre
for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TH, U.K.
| | - David R. Glowacki
- ArtSci
International Foundation, 5th Floor Mariner House, Bristol BS1 4QD, U.K.
- CiTIUS
Intelligent Technologies Research Centre, Rúa de Jenaro de La Fuente, s/n, Santiago de Compostela 15705, A Coruña, Spain
| | - Petr Slavíček
- Department
of Physical Chemistry, University of Chemistry
and Technology, Prague, Technická 5, Prague 16628, Czech Republic
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27
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Desvals A, Fortino M, Lefebvre C, Rogier J, Michelin C, Alioui S, Rousset E, Pedone A, Lemercier G, Hoffmann N. Synthesis and characterization of polymethine dyes carrying thiobarbituric and carboxylic acid moieties. NEW J CHEM 2022. [DOI: 10.1039/d2nj00684g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polymethine dyes are prepared using a convenient synthesis and characterized by physicochemical and computational methods.
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Affiliation(s)
- Arthur Desvals
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | | | - Corentin Lefebvre
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Johann Rogier
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Clément Michelin
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, 63000 Clermont-Ferrand, France
| | - Samy Alioui
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Elodie Rousset
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Alfonso Pedone
- Università di Modena e Reggio Emilia, via Campi 103, 41125 Modena, Italy
| | - Gilles Lemercier
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
| | - Norbert Hoffmann
- CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
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28
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Grabarz AM, Ośmiałowski B. Benchmarking Density Functional Approximations for Excited-State Properties of Fluorescent Dyes. Molecules 2021; 26:7434. [PMID: 34946515 PMCID: PMC8703901 DOI: 10.3390/molecules26247434] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/28/2021] [Accepted: 12/04/2021] [Indexed: 12/05/2022] Open
Abstract
This study presents an extensive analysis of the predictive power of time-dependent density functional theory in determining the excited-state properties of two groups of important fluorescent dyes, difluoroboranes and hydroxyphenylimidazo[1,2-a]pyridine derivatives. To ensure statistically meaningful results, the data set is comprised of 85 molecules manifesting diverse photophysical properties. The vertical excitation energies and dipole moments (in the electronic ground and excited states) of the aforementioned dyes were determined using the RI-CC2 method (reference) and with 18 density functional approximations (DFA). The set encompasses DFAs with varying amounts of exact exchange energy (EEX): from 0% (e.g., SVWN, BLYP), through a medium (e.g., TPSSh, B3LYP), up to a major contribution of EEX (e.g., BMK, MN15). It also includes range-separated hybrids (CAM-B3LYP, LC-BLYP). Similar error profiles of vertical energy were obtained for both dye groups, although the errors related to hydroxyphenylimidazopiridines are significantly larger. Overall, functionals including 40-55% of EEX (SOGGA11-X, BMK, M06-2X) ensure satisfactory agreement with the reference vertical excitation energies obtained using the RI-CC2 method; however, MN15 significantly outperforms them, providing a mean absolute error of merely 0.04 eV together with a very high correlation coefficient (R2 = 0.98). Within the investigated set of functionals, there is no single functional that would equally accurately determine ground- and excited-state dipole moments of difluoroboranes and hydroxyphenylimidazopiridine derivatives. Depending on the chosen set of dyes, the most accurate μGS predictions were delivered by MN15 incorporating a major EEX contribution (difluoroboranes) and by PBE0 containing a minor EEX fraction (hydroxyphenylimidazopiridines). Reverse trends are observed for μES, i.e., for difluoroboranes the best results were obtained with functionals including a minor fraction of EEX, specifically PBE0, while in the case of hydroxyphenylimidazopiridines, much more accurate predictions were provided by functionals incorporating a major EEX contribution (BMK, MN15).
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Affiliation(s)
- Anna M. Grabarz
- Faculty of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - Borys Ośmiałowski
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87100 Toruń, Poland;
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29
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Laamiri K, Garcia GA, Nahon L, Ben Houria A, Feifel R, Hochlaf M. Threshold photoelectron spectroscopy of 9-methyladenine: theory and experiment. Phys Chem Chem Phys 2021; 24:3523-3531. [PMID: 34676858 DOI: 10.1039/d1cp03729c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We present a combined experimental and theoretical study of single-photon ionization of 9-methyladenine (9MA) in the gas phase. In addition to tautomerism, several rotamers due to the rotation of the methyl group may exist. Computations show, however, that solely one rotamer contributes because of low population in the molecular beam and/or unfavorable Franck-Condon factors upon ionization. Experimentally, we used VUV radiation available at the DESIRS beamline of the synchrotron radiation facility SOLEIL to record the threshold photoelectron spectrum of this molecule between 8 and 11 eV. This spectrum consists of a well-resolved band assigned mainly to vibronic levels of the D0 cationic state, plus a contribution from the D1 state, and two large bands corresponding to the D1, D2 and D3 electronically excited states. The adiabatic ionization energy of 9MA is measured at 8.097 ± 0.005 eV in close agreement with the computed value using the explicitly correlated coupled cluster approach including core valence, scalar relativistic and zero-point vibrational energy corrections. This work sheds light on the complex pattern of the lowest doublet electronic states of 9MA+. The comparison to canonical adenine reveals that methylation induces further electronic structure complication that may be important to understand the effects of ionizing radiation and the charge distribution in these biological entities at different time scales.
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Affiliation(s)
- K Laamiri
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs-sur-Marne, France. .,Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - G A Garcia
- Synchrotron SOLEIL, L'orme des Merisiers, Saint-Aubin - BP 48 - 91192 Gif-sur-Yvette Cedex, France
| | - L Nahon
- Synchrotron SOLEIL, L'orme des Merisiers, Saint-Aubin - BP 48 - 91192 Gif-sur-Yvette Cedex, France
| | - A Ben Houria
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - R Feifel
- University of Gothenburg, Department of Physics, 412 58 Gothenburg, Sweden
| | - M Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs-sur-Marne, France.
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30
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Hu Z, Sun Z, Sun H. Simulation of Negative Ion Photoelectron Spectroscopy Using a Nuclear Ensemble Approach: Implications from a Nuclear Vibration Effect. J Phys Chem A 2021; 125:6621-6628. [PMID: 34318668 DOI: 10.1021/acs.jpca.1c04246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The negative ion photoelectron spectroscopy (NIPES) has been proven to be a powerful technique to reveal the electronic structures and spectroscopic properties of various cluster anions/radicals with very high precision. However, direct comparisons of the theoretical NIPES with experimental measurements remain challenging. Particularly the nuclear vibration effect and the ionization probability are typically ignored in reproducing NIPES. In this work, the NIPES of three representative anions (NaS5-, P2N3-, and HCPN3-) with significantly different spectral features were simulated by combining the nuclear ensemble approach (NEA) and Dyson orbitals (DOs). Overall, the simulated NIPES are in good agreement with the experimentally determined ones, confirming the robustness of such a strategy. The analysis of frontier molecular orbitals (MOs) and DOs further suggests the similar mixed characters for the first ionized doublet (D0) and adjacent D1 states of NaS5- with distributions on the side sulfur atoms. And the D0 of P2N3* is confirmed as the lowest energy σ radical state; however, the D0 of HCPN3* should possess a mixture of π and σ electrons by taking into account the nuclear vibration effect. Next, the broader vibrational distribution and stronger main vibration modes of P2N3- and HCPN3- explain why the nuclear vibration possesses a more pronounced influence in reproducing their NIPES while it has little effect on NaS5-. Last, the limitations based on the double-harmonic approximation model and density of state method were also discussed, highlighting that the ionization probability and orbital relaxation effect during the ionization process should be reasonably considered.
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Affiliation(s)
- Zhubin Hu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
| | - Zhenrong Sun
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, P. R. China
| | - Haitao Sun
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, P. R. China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 North Zhongshan Road, Shanghai 200062, P. R. China
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31
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Barone V, Puzzarini C, Mancini G. Integration of theory, simulation, artificial intelligence and virtual reality: a four-pillar approach for reconciling accuracy and interpretability in computational spectroscopy. Phys Chem Chem Phys 2021; 23:17079-17096. [PMID: 34346437 DOI: 10.1039/d1cp02507d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The established pillars of computational spectroscopy are theory and computer based simulations. Recently, artificial intelligence and virtual reality are becoming the third and fourth pillars of an integrated strategy for the investigation of complex phenomena. The main goal of the present contribution is the description of some new perspectives for computational spectroscopy, in the framework of a strategy in which computational methodologies at the state of the art, high-performance computing, artificial intelligence and virtual reality tools are integrated with the aim of improving research throughput and achieving goals otherwise not possible. Some of the key tools (e.g., continuous molecular perception model and virtual multifrequency spectrometer) and theoretical developments (e.g., non-periodic boundaries, joint variational-perturbative models) are shortly sketched and their application illustrated by means of representative case studies taken from recent work by the authors. Some of the results presented are already well beyond the state of the art in the field of computational spectroscopy, thereby also providing a proof of concept for other research fields.
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Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
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32
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Deperasińska I, Banasiewicz M, Gawryś P, Morawski O, Olas J, Kozankiewicz B. Spectra and nature of the electronic states of [1]Benzothieno[3,2-b][1]benzothiophene (BTBT): Single crystal and the aggregates. J Chem Phys 2021; 155:034504. [PMID: 34293905 DOI: 10.1063/5.0057202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Absorption, fluorescence, and phosphorescence spectra of single crystals of [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and BTBT dispersed in frozen n-nonane, n-hexadecane, and dichloromethane matrices were studied at 5 K. Observation of a new absorption band and related changes in the fluorescence to phosphorescence intensity ratio, when the concentration of BTBT in the matrix increased above 10-4M, indicated the presence of BTBT aggregates. Quantum-chemistry calculations performed for the simplest aggregate, isolated dimer, showed that its structure is similar to the "herringbone" element in the BTBT crystal unit cell and the lowest electronic excited singlet state of the dimer has the intermolecular charge-transfer character. A qualitatively different nature of this state in dimers and in crystals, when compared with the situation in BTBT monomer [locally excited (LE) state], is associated with a decrease in the intersystem crossing yield. The structured vibronic structure of phosphorescence spectra in the studied systems indicated LE character of the triplet states.
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Affiliation(s)
- Irena Deperasińska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Marzena Banasiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Paweł Gawryś
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Olaf Morawski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Joanna Olas
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Boleslaw Kozankiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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33
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Palmer MH, Hoffmann SV, Jones NC, Coreno M, de Simone M, Grazioli C, Aitken RA. The vacuum ultraviolet absorption spectrum of norbornadiene: Vibrational analysis of the singlet and triplet valence states of norbornadiene by configuration interaction and density functional calculations. J Chem Phys 2021; 155:034308. [PMID: 34293869 DOI: 10.1063/5.0053962] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A synchrotron-based vacuum ultraviolet (VUV) absorption spectrum of norbornadiene (NBD) is reported, and the extensive vibrational structure obtained has been analyzed. The previously known 5b13s-Rydberg state has been reinterpreted by comparison with our recent high-resolution photoelectron spectral analysis of the X2B1 ionic state. Additional vibrational details in the region of this Rydberg state are observed in its VUV spectrum when compared with the photoelectron 2B1 ionic state; this is attributed to the underlying valence state structure in the VUV. Valence and Rydberg state energies have been obtained by configuration interaction and time-dependent density functional theoretical methods. Several low-lying singlet valence states, especially those that arise from ππ* excitations, conventionally termed NV1 to NV4, have been examined in detail. Their Franck-Condon (FC) and Herzberg-Teller (HT) profiles have been investigated and fitted to the VUV spectrum. Estimates of the experimental 00 band positions have been made from these fits. The anomaly of the observed UV absorption by the 1A2 state of NBD is attributed to HT effects. Generally, the HT components are less than 10% of the FC terms. The calculated 5b13s lowest Rydberg state also shows a low level of HT components. The observed electron impact spectra of NBD have been analyzed in detail in terms of triplet states.
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Affiliation(s)
- Michael H Palmer
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Nykola C Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Marcello Coreno
- ISM-CNR, Instituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
| | | | | | - R Alan Aitken
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST Scotland, United Kingdom
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34
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Izadnia S, LaForge AC, Stienkemeier F, Cheeseman JR, Bloino J, Cheramy J, Jäger W, Xu Y. Unusual binary aggregates of perylene bisimide revealed by their electronic transitions in helium nanodroplets and DFT calculations. Phys Chem Chem Phys 2021; 23:13862-13872. [PMID: 34159991 DOI: 10.1039/d1cp01923f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The S1 ← S0 electronic transition of perylene bisimide (PBI) and its binary aggregates were investigated using a combination of helium nanodroplet isolation spectroscopy and computational methods. First, well-resolved vibronic bands of the PBI monomer obtained under the superfluid helium nanodroplet environment were compared to simulated vibronic spectra with anharmonic corrections of the band positions. Second, about ten sets of weaker vibronic bands were observed, which show similar vibronic patterns as that of the PBI monomer and have their band origins red-shifted by about 8 to 218 cm-1. Experimental Poisson curve analyses, performed at the origins of these new sets of bands and the PBI monomer, indicate that the carriers of these weaker red-shifted vibronic bands are binary adducts of PBI. Three types of PBI dimer structures where the electronic transition dipole moments of the two subunits are perpendicular to each other were proposed as possible carriers of these red-shifted vibronic patterns. Extensive vibronic simulations were carried out in a multi-step procedure with TD-DFT, vertical Hessian, and finally adiabatic Hessian approaches. Small red-shifted band origins and very similar vibronic patterns to that of the monomer were predicted for unusual, T-shaped, type I dimer structures and are in close agreement with the experimental data. The combined experimental and theoretical results indicate that the helium nanodroplet environment enables the formation of these unusual T-shaped dimers and stabilizes them.
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Affiliation(s)
- S Izadnia
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany.
| | - A C LaForge
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany.
| | - F Stienkemeier
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany.
| | - James R Cheeseman
- Gaussian Inc., 340 Quinnipiac St., Bldg. 40, Wallingford, Connecticut 06492-4050, USA
| | - Julien Bloino
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, 56126 Pisa, Italy
| | - J Cheramy
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
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35
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Mendes M, Kossoski F, Lozano AI, Pereira-da-Silva J, Rodrigues R, Ameixa J, Jones NC, Hoffmann SV, Ferreira da Silva F. Excited States of Bromopyrimidines Probed by VUV Photoabsorption Spectroscopy and Theoretical Calculations. Int J Mol Sci 2021; 22:6460. [PMID: 34208711 PMCID: PMC8235550 DOI: 10.3390/ijms22126460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/10/2021] [Accepted: 06/12/2021] [Indexed: 11/16/2022] Open
Abstract
We report absolute photoabsorption cross sections for gas-phase 2- and 5-bromopyrimidine in the 3.7-10.8 eV energy range, in a joint theoretical and experimental study. The measurements were carried out using high-resolution vacuum ultraviolet synchrotron radiation, with quantum chemical calculations performed through the nuclear ensemble approach in combination with time-dependent density functional theory, along with additional Franck-Condon Herzberg-Teller calculations for the first absorption band (3.7-4.6 eV). The cross sections of both bromopyrimidines are very similar below 7.3 eV, deviating more substantially from each other at higher energies. In the 7.3-9.0 eV range where the maximum cross-section is found, a single and broad band is observed for 5-bromopyrimidine, while more discernible features appear in the case of 2-bromopyrimidine. Several π* ← π transitions account for the most intense bands, while weaker ones are assigned to transitions involving the nitrogen and bromine lone pairs, the antibonding σ*Br orbital, and the lower-lying Rydberg states. A detailed comparison with the available photo-absorption data of bromobenzene is also reported. We have found significant differences regarding the main absorption band, which is more peaked in bromobenzene, becoming broader and shifting to higher energies in both bromopyrimidines. In addition, there is a significant suppression of vibrational structures and of Rydberg states in the pair of isomers, most noticeably for 2-bromopyrimidine.
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Affiliation(s)
- Mónica Mendes
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - Fábris Kossoski
- Laboratoire de Chimie et Physique Quantiques (UMR 5626), Université de Toulouse, CNRS, UPS, CEDEX 09, 31062 Toulouse, France
| | - Ana I. Lozano
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - João Pereira-da-Silva
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - Rodrigo Rodrigues
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - João Ameixa
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
| | - Nykola C. Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark; (N.C.J.); (S.V.H.)
| | - Søren V. Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark; (N.C.J.); (S.V.H.)
| | - Filipe Ferreira da Silva
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (A.I.L.); (J.P.-d.-S.); (R.R.); (J.A.); (F.F.d.S.)
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Yang Q, Fusè M, Bloino J, Barone V. Interplay of stereo-electronic, vibronic and environmental effects in tuning the chiroptical properties of an Ir(III) cyclometalated N-heterocyclic carbene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 254:119631. [PMID: 33761386 DOI: 10.1016/j.saa.2021.119631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/11/2021] [Accepted: 02/14/2021] [Indexed: 06/12/2023]
Abstract
Chiroptical spectra are among the most suitable techniques for investigating the ground and excited electronic states of chiral systems, but their interpretation is not straightforward and strongly benefits from quantum chemical simulations, provided that the employed computational model is sufficiently accurate and deals properly with stereo-electronic, vibrational averaging and environmental effects. Since the synergy among all these effects is only rarely accounted for, especially for large and flexible organometallic systems, the main aim of this contribution is to illustrate the latest developments of computational approaches rooted into the density functional theory for describing stereo-electronic effects and complemented by effective techniques to deal with vibrational modulation effects and solvatochromic shifts. In this connection, chiral iridium complexes offer an especially suitable case study in view of their bright phosphorescence, which is particularly significant for building effective light emitting diodes (OLEDs) and biomarkers and can be finely tuned by the nature of the metal ligands. For instance, a recently synthesized family of cycloiridiated complexes, KC and KD, bearing a pentahelicenic N-heterocyclic carbene (KB), has shown an enhanced long-lasting, bright phosphorescence. Deeper insights into the still unclear nature and origin of the enhancement could be gained by the interpretation of the chiroptical spectra, which is quite challenging in view of the presence of two sources of chirality, the chiral center on Ir and the chiral axis related to the helicene ligand, in addition to the relativistic effects related to the presence of the Ir center. At the same time, the large dimensions of KC and KD hamper the use of the most sophisticated (but prohibitively expensive) computational models, so that more approximate approaches must be validated on a suitable model compound. To this end, after optimizing the computational scheme on a model system devoid of the helicene moiety (KA), we have performed a comprehensive investigation of the KC and KD spectra, whose interpretation is further aided by novel graphical tools. The discussion and analysis of the results will not be focused on the theoretical background, but, rather, on practical details (specific functional, basis set, vibronic model, solvent regime) with the aim of providing general guidelines for the use of last-generation computational spectroscopy tools also by non-specialists.
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Affiliation(s)
- Qin Yang
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Marco Fusè
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Julien Bloino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
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37
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Barone V, Alessandrini S, Biczysko M, Cheeseman JR, Clary DC, McCoy AB, DiRisio RJ, Neese F, Melosso M, Puzzarini C. Computational molecular spectroscopy. ACTA ACUST UNITED AC 2021. [DOI: 10.1038/s43586-021-00034-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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38
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Zuehlsdorff TJ, Shedge SV, Lu SY, Hong H, Aguirre VP, Shi L, Isborn CM. Vibronic and Environmental Effects in Simulations of Optical Spectroscopy. Annu Rev Phys Chem 2021; 72:165-188. [DOI: 10.1146/annurev-physchem-090419-051350] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Including both environmental and vibronic effects is important for accurate simulation of optical spectra, but combining these effects remains computationally challenging. We outline two approaches that consider both the explicit atomistic environment and the vibronic transitions. Both phenomena are responsible for spectral shapes in linear spectroscopy and the electronic evolution measured in nonlinear spectroscopy. The first approach utilizes snapshots of chromophore-environment configurations for which chromophore normal modes are determined. We outline various approximations for this static approach that assumes harmonic potentials and ignores dynamic system-environment coupling. The second approach obtains excitation energies for a series of time-correlated snapshots. This dynamic approach relies on the accurate truncation of the cumulant expansion but treats the dynamics of the chromophore and the environment on equal footing. Both approaches show significant potential for making strides toward more accurate optical spectroscopy simulations of complex condensed phase systems.
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Affiliation(s)
- Tim J. Zuehlsdorff
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Sapana V. Shedge
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
| | - Shao-Yu Lu
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
| | - Hanbo Hong
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
| | - Vincent P. Aguirre
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
| | - Liang Shi
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
| | - Christine M. Isborn
- Department of Chemistry and Chemical Biology, University of California, Merced, California 95343, USA
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39
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Shedge SV, Zuehlsdorff TJ, Khanna A, Conley S, Isborn CM. Explicit environmental and vibronic effects in simulations of linear and nonlinear optical spectroscopy. J Chem Phys 2021; 154:084116. [PMID: 33639769 DOI: 10.1063/5.0038196] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accurately simulating the linear and nonlinear electronic spectra of condensed phase systems and accounting for all physical phenomena contributing to spectral line shapes presents a significant challenge. Vibronic transitions can be captured through a harmonic model generated from the normal modes of a chromophore, but it is challenging to also include the effects of specific chromophore-environment interactions within such a model. We work to overcome this limitation by combining approaches to account for both explicit environment interactions and vibronic couplings for simulating both linear and nonlinear optical spectra. We present and show results for three approaches of varying computational cost for combining ensemble sampling of chromophore-environment configurations with Franck-Condon line shapes for simulating linear spectra. We present two analogous approaches for nonlinear spectra. Simulated absorption spectra and two-dimensional electronic spectra (2DES) are presented for the Nile red chromophore in different solvent environments. Employing an average Franck-Condon or 2DES line shape appears to be a promising method for simulating linear and nonlinear spectroscopy for a chromophore in the condensed phase.
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Affiliation(s)
- Sapana V Shedge
- Chemistry and Chemical Biology, University of California Merced, Merced, California 95343, USA
| | - Tim J Zuehlsdorff
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Ajay Khanna
- Chemistry and Chemical Biology, University of California Merced, Merced, California 95343, USA
| | - Stacey Conley
- Chemistry and Chemical Biology, University of California Merced, Merced, California 95343, USA
| | - Christine M Isborn
- Chemistry and Chemical Biology, University of California Merced, Merced, California 95343, USA
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40
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Aranda D, Santoro F. Vibronic Spectra of π-Conjugated Systems with a Multitude of Coupled States: A Protocol Based on Linear Vibronic Coupling Models and Quantum Dynamics Tested on Hexahelicene. J Chem Theory Comput 2021; 17:1691-1700. [PMID: 33606542 DOI: 10.1021/acs.jctc.1c00022] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Hexahelicene is a prototype of an extended π-conjugated system with axial chirality. Its absorption (ABS) and electronic circular dichroism (ECD) spectra show vibronic features and strong nonadiabatic effects, challenging currently available computational methods. Here, we compute the nonadiabatic ABS and ECD vibronic spectra of hexahelicene in the full energy range, covering ∼2 eV and 14-18 coupled electronic states, including all of the relevant nuclear coordinates. To this end, we exploit a recently proposed protocol that uses time-dependent density functional theory to parameterize linear vibronic coupling models comprising several electronic states. Spectra are computed through quantum dynamical propagations with multiconfigurational time-dependent Hartree methods. Our results nicely reproduce the experimental spectra providing an assignment of the main observed bands. On the contrary, we document that the application of the Herzberg-Teller intensity-borrowing theory leads to large artifacts. The proposed approach is of general applicability for rigid systems and represents a viable tool for studying the photophysical properties of π-conjugated systems characterized by a dense manifold of interacting electronic states.
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Affiliation(s)
- Daniel Aranda
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Fabrizio Santoro
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
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41
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Lu IC, Tsai CN, Lin YT, Hung SY, Chao VPS, Yin CW, Luo DW, Chen HY, Endicott JF, Chen YJ. Near-IR Charge-Transfer Emission at 77 K and Density Functional Theory Modeling of Ruthenium(II)-Dipyrrinato Chromophores: High Phosphorescence Efficiency of the Emitting State Related to Spin-Orbit Coupling Mediation of Intensity from Numerous Low-Energy Singlet Excited States. J Phys Chem A 2021; 125:903-919. [PMID: 33470828 DOI: 10.1021/acs.jpca.0c05910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Efficient charge-transfer (CT) phosphorescence in the near-IR (NIR) spectral region is reported for four substituted Ru-(R-dipyrrinato) complexes, [Ru(bpy)2(R-dipy)](PF6), where bpy is 2,2'-bipyridine and the substituent R is phenyl (ph), 2,4,6-trimethylphenyl, 4-carboxyphenyl (HOOC-ph), or 4-pyridinyl. The experimentally determined phosphorescence efficiency, ιem(p) = kRAD(p)/(νem(p))3 (where kRAD(p) and νem(p) are the phosphorescence rate constant and the phosphorescence frequency, respectively), of the [Ru(bpy)2(R-dipy)]+ complexes was approximately double that of [Ru(bpy)(Am)4]2+ complexes (Am = ammine ligand) in the NIR region. Density functional theory (DFT) modeling indicated two strikingly different electronic configurations of the triplet emitting state (Te) in the two types of complexes. The Te of [Ru(bpy)2(R-dipy)]+ complexes shows a CT-type corresponding to the metal-to-ligand charge transfer (MLCT)-(Ru-(R-dipy)) and the ππ*-(R-dipy) moiety configurations, and the Te state in the [Ru(bpy)(Am)4]2+ complexes corresponds to an approximately MLCT excited state consisting of mostly MLCT-(Ru-bpy) with a minimal ππ*(bpy) contribution. DFT modeling also indicated that the low-energy singlet excited states in the Te geometry (Sn(T)) of the [Ru(bpy)2(ph-dipy)]+ complex consist of numerous CT-Sn(T)-type states of the Ru-dipy and Ru-bpy moieties, whereas the [Ru(bpy)(Am)4]2+ ions show quite simple MLCT-Sn(T)-type states of the Ru-bpy moiety. Based on experimental observations, DFT modeling, and the plain spin-orbit coupling (SOC) principle, we conclude that the remarkably high ιem(p) amplitudes of the [Ru(bpy)2(R-dipy)]+ complexes relative to those of [Ru(bpy)(Am)4]2+ complexes can be attributed to the relatively substantial contribution of intrinsic SOC-mediated intensity stealing from the numerous low-energy CT-type Sn(T) states.
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Affiliation(s)
- I-Chen Lu
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Chia Nung Tsai
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Yu-Ting Lin
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Shin-Yi Hung
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Vincent P S Chao
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Chi-Wei Yin
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
| | - Dao-Wen Luo
- Instruments Center and Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan, ROC
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC
| | - John F Endicott
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Yuan Jang Chen
- Department of Chemistry, Fu-Jen Catholic University, New Taipei City 24205, Taiwan, ROC
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42
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Schira R, Latouche C. DFT vs. TDDFT vs. TDA to simulate phosphorescence spectra of Pt- and Ir-based complexes. Dalton Trans 2021; 50:746-753. [DOI: 10.1039/d0dt03614e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A quantum investigation of the optical (mainly luminescence) properties of twelve transition metal complexes using DFT, TDDFT and TDA computations is presented. Unrestricted DFT and TDA outperform TDDFT for the investigated complexes especially when an Ir centre is present.
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Affiliation(s)
- Romain Schira
- Université de Nantes
- CNRS
- Institut des Matériaux Jean Rouxel
- IMN
- F-44000 Nantes
| | - Camille Latouche
- Université de Nantes
- CNRS
- Institut des Matériaux Jean Rouxel
- IMN
- F-44000 Nantes
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43
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de Sousa LE, de Paiva LSR, da Silva Filho DA, Sini G, de Oliveira Neto PH. Assessing the effects of increasing conjugation length on exciton diffusion: from small molecules to the polymeric limit. Phys Chem Chem Phys 2021; 23:15635-15644. [PMID: 34268543 DOI: 10.1039/d1cp01263k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organic solar cells (OSC) generally contain long-chain π-conjugated polymers as donor materials, but, more recently, small-molecule donors have also attracted considerable attention. The nature of these compounds is of crucial importance concerning the various processes that determine device performance, among which singlet exciton diffusion is one of the most relevant. The efficiency of the diffusion mechanism depends on several aspects, from system morphology to electronic structure properties, which vary importantly with molecular size. In this work, we investigated the effects of conjugation length on the exciton diffusion length through electronic structure calculations and an exciton diffusion model. By applying extrapolation procedures to thiophene and phenylene vinylene oligomer series, we investigate their electronic and optical properties from the small-molecule point of view to the polymeric limit. Several properties are calculated as a function of oligomer size, including transition energies, absorption and emission spectra, reorganization energies, exciton coupling and Förster radii. Finally, an exciton diffusion model is used to estimate diffusion lengths as a function of oligomer size and for the polymeric limit showing agreement with experimental data. Results also show that longer conjugation lengths correlate with longer exciton diffusion lengths in spite of also being associated with shorter exciton lifetimes.
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Affiliation(s)
- Leonardo Evaristo de Sousa
- Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej 301, 2800 Kongens Lyngby, Denmark
| | | | - Demétrio Antônio da Silva Filho
- Institute of Physics, University of Brasilia, 70919-970, Brasilia, Brazil. and Laboratoire de Physicochimie des Polymères et des Interfaces, EA 2528, CY Cergy Paris Université, 5 mail Gay-Lussac, 95031, Cergy-Pontoise Cedex, France and Institute for Advanced Studies, CY Cergy Paris Université, 1 rue Descartes, 95000, Neuville-sur-Oise, France
| | - Gjergji Sini
- Laboratoire de Physicochimie des Polymères et des Interfaces, EA 2528, CY Cergy Paris Université, 5 mail Gay-Lussac, 95031, Cergy-Pontoise Cedex, France
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44
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Deutsch M, Wirsing S, Kaiser D, Fink RF, Tegeder P, Engels B. Geometry relaxation-mediated localization and delocalization of excitons in organic semiconductors: A quantum chemical study. J Chem Phys 2020; 153:224104. [DOI: 10.1063/5.0028943] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- M. Deutsch
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg,, Emil-Fischer-Str. 42, D-97074 Würzburg, Germany
| | - S. Wirsing
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg,, Emil-Fischer-Str. 42, D-97074 Würzburg, Germany
| | - D. Kaiser
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg,, Emil-Fischer-Str. 42, D-97074 Würzburg, Germany
| | - R. F. Fink
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - P. Tegeder
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - B. Engels
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg,, Emil-Fischer-Str. 42, D-97074 Würzburg, Germany
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45
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Palmer MH, Coreno M, de Simone M, Grazioli C, Aitken RA, Hoffmann SV, Jones NC, Peureux C. High-level studies of the ionic states of norbornadiene and quadricyclane, including analysis of new experimental photoelectron spectra by configuration interaction and coupled cluster calculations. J Chem Phys 2020; 153:204303. [DOI: 10.1063/5.0031387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael H. Palmer
- School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, Scotland, United Kingdom
| | - Marcello Coreno
- ISM-CNR, Istituto di Struttura Della Materia, LD2 Unit, 34149 Trieste, Italy
| | | | | | - R. Alan Aitken
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland, United Kingdom
| | - Søren Vrønning Hoffmann
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Nykola C. Jones
- ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Coralyse Peureux
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, Scotland, United Kingdom
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46
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Zieleniewska A, Zhao X, Bauroth S, Wang C, Batsanov AS, Krick Calderon C, Kahnt A, Clark T, Bryce MR, Guldi DM. Resonance-Enhanced Charge Delocalization in Carbazole-Oligoyne-Oxadiazole Conjugates. J Am Chem Soc 2020; 142:18769-18781. [PMID: 33084308 DOI: 10.1021/jacs.0c04003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There are notably few literature reports of electron donor-acceptor oligoynes, even though they offer unique opportunities for studying charge transport through "all-carbon" molecular bridges. In this context, the current study focuses on a series of carbazole-(C≡C)n-2,5-diphenyl-1,3,4-oxadiazoles (n = 1-4) as conjugated π-systems in general and explores their photophysical properties in particular. Contrary to the behavior of typical electron donor-acceptor systems, for these oligoynes, the rates of charge recombination after photoexcitation increase with increasing electron donor-acceptor distance. To elucidate this unusual performance, we conducted detailed photophysical and time-dependent density functional theory investigations. Significant delocalization of the molecular orbitals along the bridge indicates that the bridging states come into resonance with either the electron donor or acceptor, thereby accelerating the charge transfer. Moreover, the calculated bond lengths reveal a reduction in bond-length alternation upon photoexcitation, indicating significant cumulenic character of the bridge in the excited state. In short, strong vibronic coupling between the electron-donating N-arylcarbazoles and the electron-accepting 1,3,4-oxadiazoles accelerates the charge recombination as the oligoyne becomes longer.
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Affiliation(s)
- Anna Zieleniewska
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, Erlangen 91058, Germany
| | - Xiaotao Zhao
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Stefan Bauroth
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, Erlangen 91058, Germany
| | - Changsheng Wang
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Andrei S Batsanov
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Christina Krick Calderon
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, Erlangen 91058, Germany
| | - Axel Kahnt
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, Leipzig 04318, Germany
| | - Timothy Clark
- Computer Chemistry Center, Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, Erlangen 91052, Germany
| | - Martin R Bryce
- Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, Erlangen 91058, Germany
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47
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Köse ME, Schanze KS. Prediction of Internal Reorganization Energy in Photoinduced Electron Transfer Processes of Molecular Dyads. J Phys Chem A 2020; 124:9478-9486. [PMID: 33141580 DOI: 10.1021/acs.jpca.0c09533] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel theoretical methodology is proposed to estimate the magnitude of internal reorganization energy for electron transfer and charge recombination processes in donor-bridge-acceptor (D-B-A) type molecular dyads. The potential energy surface for each process is plotted for the shortest path by assuming a displaced but slightly distorted harmonic oscillator model. Structural changes occurring upon photoexcitation and ionization were exploited to calculate the activation energies needed for electron transfer reactions with the aid of involved vibrational modes. D-B-A dyads consisting of octathiophene (T8) paired with three (di)imide acceptors (naphthalene diimide (NDI), benzene diimide (BDI), and naphthalimide (NI)) were studied as model systems for theoretical calculations. It has been found that T8NDI and T8BDI possess very low activation energies for both forward electron transfer and charge recombination, and hence the rates for relevant processes should be very rapid. In contrast, the activation energies for such processes for T8NI were found to be relatively large, and free energy estimations predict that the charge recombination mechanism in T8NI falls into the inverted regime of Marcus semiclassical electron transfer theory. All of the calculated properties of the dyads are in very good agreement with the available experimental data, suggesting the suitability of the proposed theoretical approach in revealing the photoinduced electron transfer mechanisms of molecular dyads.
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Affiliation(s)
| | - Kirk S Schanze
- Department of Chemistry, University of Texas at San Antonio, One UTSA Way, San Antonio, Texas 78249, United States
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48
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Sirohiwal A, Berraud-Pache R, Neese F, Izsák R, Pantazis DA. Accurate Computation of the Absorption Spectrum of Chlorophyll a with Pair Natural Orbital Coupled Cluster Methods. J Phys Chem B 2020; 124:8761-8771. [PMID: 32930590 PMCID: PMC7584356 DOI: 10.1021/acs.jpcb.0c05761] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
The
ability to accurately compute low-energy excited states of
chlorophylls is critically important for understanding the vital roles
they play in light harvesting, energy transfer, and photosynthetic
charge separation. The challenge for quantum chemical methods arises
both from the intrinsic complexity of the electronic structure problem
and, in the case of biological models, from the need to account for
protein–pigment interactions. In this work, we report electronic
structure calculations of unprecedented accuracy for the low-energy
excited states in the Q and B bands of chlorophyll a. This is achieved by using the newly developed domain-based local
pair natural orbital (DLPNO) implementation of the similarity transformed
equation of motion coupled cluster theory with single and double excitations
(STEOM-CCSD) in combination with sufficiently large and flexible basis
sets. The results of our DLPNO–STEOM-CCSD calculations are
compared with more approximate approaches. The results demonstrate
that, in contrast to time-dependent density functional theory, the
DLPNO–STEOM-CCSD method provides a balanced performance for
both absorption bands. In addition to vertical excitation energies,
we have calculated the vibronic spectrum for the Q and B bands through
a combination of DLPNO–STEOM-CCSD and ground-state density
functional theory frequency calculations. These results serve as a
basis for comparison with gas-phase experiments.
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Affiliation(s)
- Abhishek Sirohiwal
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.,Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Romain Berraud-Pache
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Róbert Izsák
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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49
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Derbali I, Hrodmarsson HR, Schwell M, Bénilan Y, Poisson L, Hochlaf M, Alikhani ME, Guillemin JC, Zins EL. Unimolecular decomposition of methyl ketene and its dimer in the gas phase: theory and experiment. Phys Chem Chem Phys 2020; 22:20394-20408. [PMID: 32914152 DOI: 10.1039/d0cp03921g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a combined theoretical and experimental investigation on the single photoionization and dissociative photoionization of gas-phase methyl ketene (MKE) and its neutral dimer (MKE2). The performed experiments entail the recording of photoelectron photoion coincidence (PEPICO) spectra and slow photoelectron spectra (SPES) in the energy regime 8.7-15.5 eV using linearly polarized synchrotron radiation. We observe both dimerization and trimerization of the monomer which brings about significantly complex and abstruse dissociative ionization patterns. These require the implementation of theoretical calculations to explore the potential energy surfaces of the monomer and dimer's neutral and ionized geometries. To this end, explicitly correlated quantum chemical methodologies involving the coupled cluster with single, double and perturbative triple excitations (R)CCSD(T)-F12 method, are utilized. An improvement in the adiabatic ionization energy of MKE is presented (AIE = 8.937 ± 0.020 eV) as well as appearance energies for multiple fragments formed through dissociative ionization of either the MKE monomer or dimer. In this regard, the synergy of experiment and theory is crucial to interpreting the obtained results. We discuss the potential astrochemical implications of this work in the context of recent advances in the field of astrochemistry and speculate on the potential presence and eventual fate of interstellar MKE molecules.
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Affiliation(s)
- Imene Derbali
- MONARIS UMR 8233 CNRS, Sorbonne Université, 4 Place Jussieu, 75252 Paris Cedex 5, France
| | - Helgi Rafn Hrodmarsson
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, BP 48, Gif sur Yvette, France and Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, The Netherlands.
| | - Martin Schwell
- LISA UMR 7583 Université Paris-Est Créteil and Université de Paris, Institut Pierre et Simon Laplace, 61 Avenue du Général de Gaulle, 94010 Créteil, France
| | - Yves Bénilan
- LISA UMR 7583 Université Paris-Est Créteil and Université de Paris, Institut Pierre et Simon Laplace, 61 Avenue du Général de Gaulle, 94010 Créteil, France
| | - Lionel Poisson
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191 Gif-sur-Yvette, France
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs sur Marne, France.
| | | | - Jean-Claude Guillemin
- Univ Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR-UMR6226, F-35000 Rennes, France
| | - Emilie-Laure Zins
- MONARIS UMR 8233 CNRS, Sorbonne Université, 4 Place Jussieu, 75252 Paris Cedex 5, France
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Yang Q, Fusè M, Bloino J. Theoretical Investigation of the Circularly Polarized Luminescence of a Chiral Boron Dipyrromethene (BODIPY) Dye. Front Chem 2020; 8:801. [PMID: 33102435 PMCID: PMC7522172 DOI: 10.3389/fchem.2020.00801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/30/2020] [Indexed: 01/11/2023] Open
Abstract
Over the last decade, molecules capable of emitting circularly polarized light have attracted growing attention for potential technological and biological applications. The efficiency of such devices depend on multiple parameters, in particular the magnitude and wavelength of the peak of emitted light, and also on the dissymmetry factor for chiral applications. In light of these considerations, molecular systems with tunable optical properties, preferably in the visible spectral region, are particularly appealing. This is the case of boron dipyrromethene (BODIPY) dyes, which exhibit large molecular absorption coefficients, have high fluorescence yields, are very stable, both thermally and photochemically, and can be easily functionalized. The latter property has been extensively exploited in the literature to produce chromophores with a wide range of optical properties. Nevertheless, only a few chiral BODIPYs have been synthetized and investigated so far. Using a recently reported axially chiral BODIPY derivative where an axially chiral BINOL unit has been attached to the chromophore unit, we present a comprehensive computational protocol to predict and interpret the one-photon absorption and emission spectra, together with their chiroptical counterparts. From the physico-chemical properties of this molecule, it will be possible to understand the origin of the circularly polarized luminescence better, thus helping to fine-tune the properties of interest. The sensitivity of such processes require accurate results, which can be achieved through a proper account of the vibrational structure in optical spectra. Methodologies to compute vibrationally-resolved electronic spectra can now be applied on relatively large chromophores, such as BODIPYs, but require more extensive computational protocols. For this reason, particular attention is paid in the description of the different steps of the protocol, and the potential pitfalls. Finally, we show how, by means of appropriate tools and approaches, data from intermediate steps of the simulation of the final spectra can be used to obtain further insights into the properties of the molecular system under investigation and the origin of the visible bands.
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Affiliation(s)
- Qin Yang
- Scuola Normale Superiore, Pisa, Italy
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