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Hu Y, Wang Z, Wang F, Meissner L. Triple Electron Attachments with a New Intermediate-Hamiltonian Fock-Space Coupled-Cluster Method. J Phys Chem A 2024. [PMID: 39270002 DOI: 10.1021/acs.jpca.4c03772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2024]
Abstract
The implementation of a new intermediate-Hamiltonian Fock-space coupled-cluster (IHFSCC) scheme for the (3,0) sector of the Fock space is reported. In this IHFSCC approach, the three-body contributions in the cluster operator S(3,0) corresponding to the (3,0) sector of the Fock space are considered, while S(1,0) and S(2,0) at the (1,0) and (2,0) level only include one- and two-body operators. By introducing a suitable partition of the wave operator, the intermediate Hamiltonian, which only depends on the two-body operator of S(1,0), is obtained. S(2,0) and S(3,0) are not required within this new IHFSCC scheme, and a large reference space can be possibly employed. The performance of this (3,0) IHFSCC method in calculating triple ionization potentials and excitation energies for atoms and cations with a ground p3 configuration as well as adiabatic excitation energies for some molecules is investigated. The effect of the number of active virtual orbitals and three different types of orbitals, i.e., reference orbitals, restricted open-shell Hartree-Fock orbitals (ROHF) of the target systems, and canonicalized ROHF orbitals, on IHFSCC results, is also studied. Our calculations indicate that reasonable results can be achieved with this (3,0) IHFSCC method when a minimal reference space is employed. Further increasing the number of active orbitals does not necessarily improve the results. In addition, the IHFSCC results using canonicalized ROHF orbitals generally agree well with reference values, and they are not very sensitive to the number of active orbitals compared with results using the reference orbitals. The new (3,0) IHFSCC method can be applied to open-shell systems with three unpaired electrons with reasonable accuracy at a relatively low computational cost.
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Affiliation(s)
- Yanmei Hu
- Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu 610065, People's Republic of China
| | - Zhifan Wang
- College of Chemistry and Life Science, Chengdu Normal University, Chengdu 611130, People's Republic of China
| | - Fan Wang
- Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu 610065, People's Republic of China
| | - Leszek Meissner
- Institute of Physics, Nicholaus Copernicus University, Grudziadzka 5/7, Toruń 87-100, Poland
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2
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Leitner J, Dempwolff AL, Dreuw A. Fourth-Order Algebraic Diagrammatic Construction for Electron Detachment and Attachment: The IP- and EA-ADC(4) Methods. J Phys Chem A 2024; 128:7680-7690. [PMID: 39213621 DOI: 10.1021/acs.jpca.4c03037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
We present a non-Dyson fourth-order algebraic diagrammatic construction formulation of the electron propagator, featuring the distinct IP- and EA-ADC(4) schemes for the treatment of ionization and electron attachment processes. The algebraic expressions have been derived automatically using the intermediate state representation approach and implemented in the Q-Chem quantum-chemical program package. The performance of the novel methods is assessed with respect to high-level reference data for ionization potentials and electron affinities of closed- and open-shell systems. While only minor improvements over the corresponding third-order methods are observed for one-hole ionization and one-particle electron attachment processes from closed-shell systems (MAEIP-ADC(4) = 0.27 eV and MAEEA-ADC(4) = 0.05 eV), a significantly enhanced performance is found in case of open-shell reference states (MAEIP-ADC(4) = 0.11 eV and MAEEA-ADC(4) = 0.02 eV). A particularly appealing feature of the novel methods is their accurate treatment of satellite transitions. For closed-shell reference states, we obtain accuracies of MAEIP-ADC(4) = 0.81 eV and MAEEA-ADC(4) = 0.27 eV, while in case of open-shell reference states, mean absolute errors of MAEIP-ADC(4) = 0.15 eV and MAEEA-ADC(4) = 0.27 eV are found.
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Affiliation(s)
- Jonas Leitner
- Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
| | - Adrian L Dempwolff
- Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University, Im Neuenheimer Feld 205, 69120 Heidelberg, Germany
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3
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Kumar D, Gupta AK. A unique approach to address avoided crossings in the charge stabilization curve for LUMO identification. J Chem Phys 2024; 161:094108. [PMID: 39230371 DOI: 10.1063/5.0225287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Accepted: 08/22/2024] [Indexed: 09/05/2024] Open
Abstract
In quantum chemistry, Lowest Unoccupied Molecular Orbital (LUMO) is important for studying various chemical processes, including photochemical reactions, electron attached states, and electron excites states. Recently, an effective method has been introduced that involves the use of the Parametric Equation of Motion (PEM) in conjunction with the nuclear charge stabilization method for precise identification of true LUMO. However, the inclusion of extra diffuse functions in the basis set, which is necessary for describing electron-attached and electron-excited states, can cause issues due to the presence of the same symmetry states, leading to avoided crossing. Identifying the true LUMO among these avoided crossings is challenging due to the mixing of states and the exchange of their orbital character. This article introduces a modification of the PEM to identify the true LUMO by preventing the stabilization of specific states involved in avoided crossings. The present method is highly effective and requires minimal computational cost.
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Affiliation(s)
- Deepak Kumar
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Ashish Kumar Gupta
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, India
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4
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Vu K, Pandian J, Zhang B, Annas C, Parker AJ, Mancini JS, Wang EB, Saldana-Greco D, Nelson ES, Springsted G, Lischka H, Plasser F, Parish CA. Multireference Averaged Quadratic Coupled Cluster (MR-AQCC) Study of the Geometries and Energies for ortho-, meta- and para-Benzyne. J Phys Chem A 2024. [PMID: 39240216 DOI: 10.1021/acs.jpca.4c04099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2024]
Abstract
The diradical benzyne isomers are excellent prototypes for evaluating the ability of an electronic structure method to describe static and dynamic correlation. The benzyne isomers are also interesting molecules with which to study the fundamentals of through-space and through-bond diradical coupling that is important in so many electronic device applications. In the current study, we utilize the multireference methods MC-SCF, MR-CISD, MR-CISD+Q, and MR-AQCC with an (8,8) complete active space that includes the σ, σ*, π and π* orbitals, to characterize the electronic structure of ortho-, meta- and para-benzyne. We also determine the adiabatic and vertical singlet-triplet splittings for these isomers. MR-AQCC and MR-CISD+Q produced energy gaps in good agreement with previously obtained experimental values. Geometries, orbital energies and unpaired electron densities show significant through-space coupling in the o- and m-benzynes, while p-benzyne shows through-bond coupling, explaining the dramatically different singlet-triplet gaps between the three isomers.
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Affiliation(s)
- Khanh Vu
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Joshua Pandian
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Boyi Zhang
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Christina Annas
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Anna J Parker
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - John S Mancini
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Evan B Wang
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Diomedes Saldana-Greco
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Emily S Nelson
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Greg Springsted
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Felix Plasser
- Department of Chemistry, Loughborough University, Ashby Road, Loughborough LE11 3TU, Leicestershire, U.K
| | - Carol A Parish
- Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States
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5
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Ünal A, Bozkaya U. Equation-of-motion orbital-optimized coupled-cluster doubles method with the density-fitting approximation: An efficient implementation. J Comput Chem 2024. [PMID: 39235313 DOI: 10.1002/jcc.27495] [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: 05/06/2024] [Revised: 06/13/2024] [Accepted: 08/18/2024] [Indexed: 09/06/2024]
Abstract
Orbital-optimized coupled-cluster methods are very helpful for theoretical predictions of the molecular properties of challenging chemical systems, such as excited states. In this research, an efficient implementation of the equation-of-motion orbital-optimized coupled-cluster doubles method with the density-fitting (DF) approach, denoted by DF-EOM-OCCD, is presented. The computational cost of the DF-EOM-OCCD method for excitation energies is compared with that of the conventional EOM-OCCD method. Our results demonstrate that DF-EOM-OCCD excitation energies are dramatically accelerated compared to EOM-OCCD. There are almost 17-fold reductions for theC 5 H 12 $$ {\mathrm{C}}_5{\mathrm{H}}_{12} $$ molecule in an aug-cc-pVTZ basis set with the RHF reference. This dramatic performance improvement comes from the reduced cost of integral transformation with the DF approach and the efficient evaluation of the particle-particle ladder (PPL) term, which is the most expensive term to evaluate. Further, our results show that the DF-EOM-OCCD approach is very helpful for the computation of excitation energies in open-shell molecular systems. Overall, we conclude that our new DF-EOM-OCCD implementation is very promising for the study of excited states in large-sized challenging chemical systems.
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Affiliation(s)
- Aslı Ünal
- Department of Chemistry, Hacettepe University, Ankara, Turkey
| | - Uğur Bozkaya
- Department of Chemistry, Hacettepe University, Ankara, Turkey
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6
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Flint AR, Westbrook BR, Fortenberry RC. Theoretical Rotational and Vibrational Spectral Data for the Hypermagnesium Oxide Species Mg 2O and Mg 2O . Chemphyschem 2024; 25:e202400479. [PMID: 38801234 DOI: 10.1002/cphc.202400479] [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: 04/26/2024] [Revised: 05/22/2024] [Accepted: 05/26/2024] [Indexed: 05/29/2024]
Abstract
While magnesium is astronomically observed in small molecules, it largely serves as a contributor to silicate grains, though how these grains form is not well-understood. The smallest hypermagnesium oxide compounds (Mg2 ${{}_{2}}$ O/Mg2 ${{}_{2}}$ O+ ${{}^{+}}$ ) may play a role in silicate formation, but little vibrational reference data exist. As such, anharmonic spectroscopic data are computed forX ˜ 1 Σ g + ${{{\tilde{\rm {X}}}}^1 {\rm{\Sigma }}_g^+ }$ Mg2 ${{}_{2}}$ O,a ˜ 1 Σ u + ${{{\tilde{\rm {a}}}}^1 {\rm{\Sigma }}_u^+ }$ Mg2 ${{}_{2}}$ O, andX ˜ 2 Σ g + ${{{\tilde{\rm {X}}}}^2 {\rm{\Sigma }}_g^+ }$ Mg2 ${{}_{2}}$ O+ ${{}^{+}}$ using quartic force fields (QFFs). Explicitly-correlated coupled-cluster QFFs for the neutral species perform well, implying that full multireference treatment may not be necessary for such systems if enough electron correlation is included. Equation-of-motion ionization potential (EOMIP) methods forX ˜ 2 Σ g + ${{{\tilde{\rm {X}}}}^2 {\rm{\Sigma }}_g^+ }$ Mg2 ${{}_{2}}$ O+ ${{}^{+}}$ QFFs circumvent previous symmetry breaking issues even in explicitly-correlated coupled-cluster results, motivating the need for EOMIP treatments at minimum for such systems. All three species are found to have high-intensity vibrational frequencies. Even so, the highly intense frequency (X ˜ 1 Σ g + ${{{\tilde{\rm {X}}}}^1 {\rm{\Sigma }}_g^+ }$ Mg2 ${{}_{2}}$ O: 894.7 cm-1/11.18 μm;a ˜ 1 Σ u + ${{{\tilde{\rm {a}}}}^1 {\rm{\Sigma }}_u^+ }$ Mg2 ${{}_{2}}$ O: 915.0 cm-1/10.91 μm) for either neutral state may be astronomically obscured by the polycyclic aromatic hydrocarbon 11.2 μm band. Mg2 ${{}_{2}}$ O+ ${{}^{+}}$ may be less susceptible to such obfuscation, and itsν 1 ${{\nu }_{1}}$ intensity is computed to be a massive 4793 km mol-1.
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Affiliation(s)
- Athena R Flint
- Department of Chemistry & Biochemistry, University of Mississippi, University, MS 38655, USA
| | - Brent R Westbrook
- The Open Force Field Initiative, Open Molecular Software Foundation, Davis, CA 95616, USA
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, University, MS 38655, USA
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7
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Zhao T, Matthews DA. Analytic Gradients for Equation-of-Motion Coupled Cluster with Single, Double, and Perturbative Triple Excitations. J Chem Theory Comput 2024. [PMID: 39214857 DOI: 10.1021/acs.jctc.4c00752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Understanding the process of molecular photoexcitation is crucial in various fields, including drug development, materials science, photovoltaics, and more. The electronic vertical excitation energy is a critical property, for example in determining the singlet-triplet gap of chromophores. However, a full understanding of excited-state processes requires additional explorations of the excited-state potential energy surface and electronic properties, which is greatly aided by the availability of analytic energy gradients. Owing to its robust high accuracy over a wide range of chemical problems, equation-of-motion coupled cluster with single and double excitations (EOM-CCSD) is a powerful method for predicting excited-state properties, and the implementation of analytic gradients of many EOM-CCSD variants (excitation energies, ionization potentials, electron attachment energies, etc.) along with numerous successful applications highlights the flexibility of the method. In specific cases where a higher level of accuracy is needed or in more complex electronic structures, the inclusion of triple excitations becomes essential, for example, in the EOM-CCSD* approach of Saeh and Stanton. In this work, we derive and implement for the first time the analytic gradients of EOMEE-CCSD*, which also provides a template for analytic gradients of related excited-state methods with perturbative triple excitations. The capabilities of analytic EOMEE-CCSD* gradients are illustrated by several representative examples.
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Affiliation(s)
- Tingting Zhao
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75205, United States
| | - Devin A Matthews
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75205, United States
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8
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Monti M, Biancorosso L, Coccia E. Time-Resolved Circular Dichroism in Molecules: Experimental and Theoretical Advances. Molecules 2024; 29:4049. [PMID: 39274897 PMCID: PMC11396666 DOI: 10.3390/molecules29174049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/22/2024] [Accepted: 08/24/2024] [Indexed: 09/16/2024] Open
Abstract
Following changes in chirality can give access to relevant information on the function or reactivity of molecular systems. Time-resolved circular dichroism (TRCD) spectroscopy proves to be a valid tool to achieve this goal. Depending on the class of molecules, different temporal ranges, spanning from seconds to femtoseconds, need to be investigated to observe such chiroptical changes. Therefore, over the years, several approaches have been adopted to cover the timescale of interest, especially based on pump-probe schemes. Moreover, various theoretical approaches have been proposed to simulate and explain TRCD spectra, including linear and non-linear response methods as well as non-adiabatic molecular dynamics. In this review, an overview on both experimental and theoretical advances in the TRCD field is provided, together with selected applications. A discussion on future theoretical developments for TRCD is also given.
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Affiliation(s)
- Marta Monti
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Leonardo Biancorosso
- Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Emanuele Coccia
- Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
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9
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Skrzyński G, Musial M. Fock Space Coupled-Cluster Method for the Ground and Excited States of the NaMg + Molecular Cation. J Phys Chem A 2024; 128:6972-6980. [PMID: 39119821 PMCID: PMC11345837 DOI: 10.1021/acs.jpca.4c04275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 08/01/2024] [Accepted: 08/02/2024] [Indexed: 08/10/2024]
Abstract
This study presents a theoretical investigation of the potential energy curves (PECs) and spectroscopic constants of the NaMg+ molecular cation using the intermediate Hamiltonian Fock space coupled-cluster method with singles and doubles within the (2,0) sector [IH-FS-CCSD(2,0)]. The NaMg+ cation has gained scientific interest due to its potential applications in ultracold chemistry, yet it remains experimentally unexplored. We computed 20 lowest-lying PECs and assigned them to 10 dissociation limits. Our results demonstrated high accuracy, and computed curves are smooth and continuous over the entire range of interatomic distances. The study validates the effectiveness of the IH-FS-CCSD(2,0) method in describing PECs of diatomic molecular cations composed of alkali and alkaline earth metals and provides a solid theoretical foundation for further studies of NaMg+ and similar systems.
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Affiliation(s)
- Grzegorz Skrzyński
- Institute of Chemistry, University
of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
| | - Monika Musial
- Institute of Chemistry, University
of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
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Hirao K, Nakajima T, Chan B. Exploiting the Correlation between the 1s, 2s, and 2p Energies for the Prediction of Core-Level Binding Energies of Si, P, S, and Cl species. J Phys Chem A 2024; 128:6879-6897. [PMID: 39120958 DOI: 10.1021/acs.jpca.4c03252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2024]
Abstract
The binding energies (BEs) of the 1s, 2s, and 2p core electrons of third-period elements (Si, P, S, Cl) were calculated using Hartree-Fock (HF) and B3LYP, BH&HLYP, and LC-BOP ΔSCF, and the shifted KS ΔSCF methods. Linear relationships between two BEs were derived and compared with the Auger parameter. The derived lines are essentially parallel, with only the intercepts differing. The difference in intercepts is due to the lack of electron correlation effects in HF and the self-interaction errors (SIEs) of the functional. The slope is the slope of the linear relationship between the chemical shifts. The straight lines between the 2s and 2p BEs also coincided with the Auger parameter lines, which have a slope of 1 by definition and an intercept being the difference between the 2s and 2p BEs. The shifted KS ΔSCF scheme compensates for SIEs, yielding equations that are approximately invariant. The calculated average gaps for the 2s and 2p BEs are 51.21 eV for Si, 57.48 eV for P, 63.85 eV for S, and 70.48 eV for Cl. The straight lines representing the relationships between the BEs of the 1s and 2s and 1s and 2p electrons are also parallel to each other in ΔSCF and converge into a single line in the shifted ΔSCF scheme. However, these lines are steeper than the Auger parameter line. The derived relationships can be used to predict unknown BEs, which we have applied to many molecules. The results are highly accurate, with mean absolute errors (MAEs) of less than 0.2 eV compared to experimental values.
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Affiliation(s)
- Kimihiko Hirao
- Fukui Institute for Fundamental Chemistry, Kyoto University, Takano, Nishihiraki-cho 34-4, Sakyo-ku, Kyoto 606-8103, Japan
- RIKEN Center for Computational Science, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe 650-0047, Japan
| | - Takahito Nakajima
- RIKEN Center for Computational Science, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe 650-0047, Japan
| | - Bun Chan
- RIKEN Center for Computational Science, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe 650-0047, Japan
- Graduate School of Engineering, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan
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11
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Curchod BFE, Orr-Ewing AJ. Perspective on Theoretical and Experimental Advances in Atmospheric Photochemistry. J Phys Chem A 2024; 128:6613-6635. [PMID: 39021090 PMCID: PMC11331530 DOI: 10.1021/acs.jpca.4c03481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 07/20/2024]
Abstract
Research that explores the chemistry of Earth's atmosphere is central to the current understanding of global challenges such as climate change, stratospheric ozone depletion, and poor air quality in urban areas. This research is a synergistic combination of three established domains: earth observation, for example, using satellites, and in situ field measurements; computer modeling of the atmosphere and its chemistry; and laboratory measurements of the properties and reactivity of gas-phase molecules and aerosol particles. The complexity of the interconnected chemical and photochemical reactions which determine the composition of the atmosphere challenges the capacity of laboratory studies to provide the spectroscopic, photochemical, and kinetic data required for computer models. Here, we consider whether predictions from computational chemistry using modern electronic structure theory and nonadiabatic dynamics simulations are becoming sufficiently accurate to supplement quantitative laboratory data for wavelength-dependent absorption cross-sections, photochemical quantum yields, and reaction rate coefficients. Drawing on presentations and discussions from the CECAM workshop on Theoretical and Experimental Advances in Atmospheric Photochemistry held in March 2024, we describe key concepts in the theory of photochemistry, survey the state-of-the-art in computational photochemistry methods, and compare their capabilities with modern experimental laboratory techniques. From such considerations, we offer a perspective on the scope of computational (photo)chemistry methods based on rigorous electronic structure theory to become a fourth core domain of research in atmospheric chemistry.
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12
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Bogo N, Stein CJ. Benchmarking DFT-based excited-state methods for intermolecular charge-transfer excitations. Phys Chem Chem Phys 2024; 26:21575-21588. [PMID: 39082837 DOI: 10.1039/d4cp01866d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Intermolecular charge-transfer is a highly important process in biology and energy-conversion applications where generated charges need to be transported over several moieties. However, its theoretical description is challenging since the high accuracy required to describe these excited states must be accessible for calculations on large molecular systems. In this benchmark study, we identify reliable low-scaling computational methods for this task. Our reference results were obtained from highly accurate wavefunction calculations that restrict the size of the benchmark systems. However, the density-functional theory based methods that we identify as accurate can be applied to much larger systems. Since targeting charge-transfer states requires the unambiguous classification of an excited state, we first analyze several charge-transfer descriptors for their reliability concerning intermolecular charge-transfer and single out the charge-transfer distance calculated based on the variation of electron density upon excitation (DCT) as an optimal choice for our purposes. In general, best results are obtained for orbital-optimized methods and among those, the maximum overlap method proved to be the most numerically stable variant when using the initial MOs as reference orbitals. Favorable error cancellation with optimally-tuned range-separated hybrid functionals and a rather small basis set can provide an economical yet reasonable wavefunction when using time-dependent density functional theory, which provides relevant information about the excited-state character to be used in the orbital-optimized methods. The qualitative agreement makes these fast calculations attractive for high-throughput screening applications.
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Affiliation(s)
- Nicola Bogo
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
- Department of Chemistry and Catalysis Research Center, TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany.
| | - Christopher J Stein
- Department of Chemistry and Catalysis Research Center, TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany.
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13
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Garcia-Alvarez JC, Gozem S. Absorption Intensities of Organic Molecules from Electronic Structure Calculations versus Experiments: the Effect of Solvation, Method, Basis Set, and Transition Moment Gauge. J Chem Theory Comput 2024; 20. [PMID: 39141425 PMCID: PMC11360136 DOI: 10.1021/acs.jctc.4c00642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/24/2024] [Accepted: 07/25/2024] [Indexed: 08/15/2024]
Abstract
Recently, we derived experimental oscillator strengths (OSs) from well-defined UV-visible absorption spectral peaks of 100 molecules in solution. Here, we focus on a subset of transitions with the highest reliability to further benchmark the OSs from several wave function methods and density functionals. We consider multiple basis sets, transition moment gauges (length, velocity, and mixed), and solvent corrections. Most transitions in the comparison set come from conjugated molecules and have π → π* character. We use an automated algorithm to assign computed transitions to experimental bands. OSs computed using the Tamm-Dancoff approximation (TDA), CIS, or EOM-CCSD exhibited a strong gauge dependence, which is diminished in linear response theories (TD-DFT, TD-HF, and to a smaller degree LR-CCSD). OSs calculated from TD-DFT with PCM solvent models are systematically larger than apparent OSs derived from experimental spectra. For example, fcomp from hybrid functionals and PCM have mean absolute errors that are ∼10% of n·fexp, where n is a solvent refractive index factor that arises from the energy flux of the radiation field in a dielectric (solvent). Theoretical cavity field corrections considering spherical cavities do not improve the agreement between computed and experimental data. Corrections that account for the molecular shape and the direction of transition dipole moments, or that explicitly account for the effect of solvent molecules on the local field, should be more appropriate.
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Affiliation(s)
| | - Samer Gozem
- Department of Chemistry, Georgia
State University, Atlanta, Georgia 30302, United States
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14
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Sarangi R, Maity S, Acharya A. Machine Learning Approach to Vertical Energy Gap in Redox Processes. J Chem Theory Comput 2024; 20:6747-6755. [PMID: 39044422 PMCID: PMC11325558 DOI: 10.1021/acs.jctc.4c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
A straightforward approach to calculating the free energy change (ΔG) and reorganization energy of a redox process is linear response approximation (LRA). However, accurate prediction of redox properties is still challenging due to difficulties in conformational sampling and vertical energy-gap sampling. Expensive hybrid quantum mechanical/molecular mechanical (QM/MM) calculations are typically employed in sampling energy gaps using conformations from simulations. To alleviate the computational cost associated with the expensive QM method in the QM/MM calculation, we propose machine learning (ML) methods to predict the vertical energy gaps (VEGs). We tested several ML models to predict the VEGs and observed that simple models like linear regression show excellent performance (mean absolute error ∼0.1 eV) in predicting VEGs in all test systems, even when using features extracted from cheaper semiempirical methods. Our best ML model (extra trees regressor) shows a mean absolute error of around 0.1 eV while using features from the cheapest QM method. We anticipate our approach can be generalized to larger macromolecular systems with more complex redox centers.
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Affiliation(s)
- Ronit Sarangi
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Suman Maity
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Atanu Acharya
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, United States
- BioInspired Syracuse, Syracuse University, Syracuse, New York 13244, United States
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15
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Kabir M, Ghosh P, Gozem S. Electronic Structure Methods for Simulating Flavin's Spectroscopy and Photophysics: Comparison of Multi-reference, TD-DFT, and Single-Reference Wave Function Methods. J Phys Chem B 2024; 128:7545-7557. [PMID: 39074870 PMCID: PMC11317985 DOI: 10.1021/acs.jpcb.4c03748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 07/14/2024] [Accepted: 07/22/2024] [Indexed: 07/31/2024]
Abstract
The use of flavins and flavoproteins in photocatalytic, sensing, and biotechnological applications has led to a growing interest in computationally modeling the excited-state electronic structure and photophysics of flavin. However, there is limited consensus regarding which computational methods are appropriate for modeling flavin's photophysics. We compare the energies of low-lying excited states of flavin computed with time-dependent density functional theory (TD-DFT), equation-of-motion coupled cluster (EOM-EE-CCSD), scaled opposite-spin configuration interaction [SOS-CIS(D)], multiconfiguration pair-density functional theory (MC-PDFT), and several multireference perturbation theory (MR-PT2) methods. In the first part, we focus on excitation energies of the first singlet excited state (S1) of five different redox and protonation states of flavin, with the goal of finding a suitable active space for MR-PT2 calculations. In the second part, we construct two sets of one-dimensional potential energy surfaces connecting the S0 and S1 equilibrium geometries (S0-S1 path) and the S1 (π,π*) and S2 (n,π*) equilibrium geometries (S1-S2 path). The first path therefore follows a Franck-Condon active mode of flavin while the second path maps crossings points between low-lying singlet and triplet states in flavin. We discuss the similarities and differences in the TD-DFT, EOM-EE-CCSD, SOS-CIS(D), MC-PDFT and MR-PT2 energy profiles along these paths. We find that (TD-)DFT methods are suitable for applications such as simulating the spectra of flavins but are inconsistent with several other methods when used for some geometry optimizations and when describing the energetics of dark (n,π*) states. MR-PT2 methods show promise for the simulation of flavin's low-lying excited states, but the selection of orbitals for the active space and the number of roots used for state averaging must be done carefully to avoid artifacts. Some properties, such as the intersystem crossing geometry and energy between the S1 (π,π*) and T2 (n,π*) states, may require additional benchmarking before they can be determined quantitatively.
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Affiliation(s)
- Mohammad
Pabel Kabir
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, United States
| | - Paulami Ghosh
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, United States
| | - Samer Gozem
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, United States
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16
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Manisha, Manohar PU. Spin-flip equation-of-motion coupled cluster method with singles, doubles and (full) triples: computational implementation and some pilot applications. Phys Chem Chem Phys 2024; 26:21204-21212. [PMID: 39073075 DOI: 10.1039/d4cp02265c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
We present our computational implementation of the spin-flip (SF) equation-of-motion (EOM) coupled-cluster (CC) method with singles, doubles, and (full) triples (SDT) within Q-CHEM. The inclusion of triples not only enhances the quantitative accuracy of the SF-EOM-CCSD method but also provides correct qualitative trends in the energy gaps between strongly degenerate states. To assess the accuracy, we compare our SF-EOM-CCSDT results with full configuration interaction (FCI) and complete-active-space self-consistent field second-order (CASSCF-SO) CI benchmarks to study the adiabatic energy gaps in CH2 and NH2+ diradicals, vertical excitation energies in CH radicals and the bond dissociation of the HF molecule. We have implemented SF-EOM-CCSDT using both the conventional double precision (DP) and the single precision (SP) algorithms. The use of SP does not introduce any significant errors in energies and energy gaps, and, due to low cost (relative to DP), turns out to be a promising approach to widen the applicability of EOM-CCSDT to bigger molecules.
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Affiliation(s)
- Manisha
- Department of Chemistry, Birla Institute of Technology & Science-Pilani, Pilani, Rajasthan 333031, India.
| | - Prashant Uday Manohar
- Department of Chemistry, Birla Institute of Technology & Science-Pilani, Pilani, Rajasthan 333031, India.
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17
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Manna A, Jangid B, Pant R, Dutta AK. Efficient State-Specific Natural Orbital Based Equation of Motion Coupled Cluster Method for Core-Ionization Energies: Theory, Implementation, and Benchmark. J Chem Theory Comput 2024. [PMID: 39073757 DOI: 10.1021/acs.jctc.4c00546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
We have implemented a reduced-cost partial triples correction scheme to the equation of motion coupled cluster method for core-ionization energy based on state-specific natural orbitals. The second-order Algebraic Diagrammatic Construction (ADC) method is used to generate the state-specific natural orbital, which provides quicker convergence of the core-IP value with respect to the size of the virtual space than that observed in standard MP2-based natural orbitals. The error due to truncation of the virtual orbital can be reduced by using a perturbative correction. The accuracy of the method can be controlled by a single threshold, and there is a black box to use. The inclusion of the partial triples correction in the natural orbital based EOM-CCSD method greatly improves the agreement of the results with the experiment. The efficiency of the present implementation is demonstrated by calculating the core-ionization energy of a molecule containing 60 atoms and more than 2000 basis functions.
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Affiliation(s)
- Amrita Manna
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Bhavnesh Jangid
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Rakesh Pant
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Achintya Kumar Dutta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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18
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Tomaník L, Pugini M, Mudryk K, Thürmer S, Stemer D, Credidio B, Trinter F, Winter B, Slavíček P. Liquid-jet photoemission spectroscopy as a structural tool: site-specific acid-base chemistry of vitamin C. Phys Chem Chem Phys 2024; 26:19673-19684. [PMID: 38963770 PMCID: PMC11267885 DOI: 10.1039/d4cp01521e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Accepted: 06/12/2024] [Indexed: 07/06/2024]
Abstract
Liquid-jet photoemission spectroscopy (LJ-PES) directly probes the electronic structure of solutes and solvents. It also emerges as a novel tool to explore chemical structure in aqueous solutions, yet the scope of the approach has to be examined. Here, we present a pH-dependent liquid-jet photoelectron spectroscopic investigation of ascorbic acid (vitamin C). We combine core-level photoelectron spectroscopy and ab initio calculations, allowing us to site-specifically explore the acid-base chemistry of the biomolecule. For the first time, we demonstrate the capability of the method to simultaneously assign two deprotonation sites within the molecule. We show that a large change in chemical shift appears even for atoms distant several bonds from the chemically modified group. Furthermore, we present a highly efficient and accurate computational protocol based on a single structure using the maximum-overlap method for modeling core-level photoelectron spectra in aqueous environments. This work poses a broader question: to what extent can LJ-PES complement established structural techniques such as nuclear magnetic resonance? Answering this question is highly relevant in view of the large number of incorrect molecular structures published.
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Affiliation(s)
- Lukáš Tomaník
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic.
| | - Michele Pugini
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Karen Mudryk
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Stephan Thürmer
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, 606-8502 Kyoto, Japan
| | - Dominik Stemer
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Bruno Credidio
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Florian Trinter
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Bernd Winter
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Petr Slavíček
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic.
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19
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Kumar D, Banuary M, Gupta AK. An Innovative Approach for Precise Identification of the Lowest Unoccupied Molecular Orbital Using the Parametric Equation of Motion. J Chem Theory Comput 2024; 20:6009-6019. [PMID: 38982770 DOI: 10.1021/acs.jctc.4c00470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
The lowest unoccupied molecular orbital (LUMO) plays a crucial role in quantum chemistry, but current quantum chemistry calculations fail to provide useful virtual orbitals, making it challenging to explore various processes such as photochemical reactions, electron attachment, reduction, or excitation processes. The LUMO obtained from the self-consistent field (SCF) solution can not be relied upon and needs to be identified as they are often present among the continuum states having almost similar energies. The nuclear charge stabilization method has been proven useful in identifying LUMO. Herein, we have proposed the application of parametric equations of motion (PEM) in conjunction with nuclear charge stabilization method to identify the LUMO obtained from the SCF solution exhibiting stability with different basis sets including diffuse functions.
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Affiliation(s)
- Deepak Kumar
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Mwdansar Banuary
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Ashish Kumar Gupta
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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20
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Gustafson A, Sburlati S, Kahr B. Computed Gyration Tensors of Knotted Chiral and Achiral Topological Stereoisomers of C 60 Cyclocarbons. Chemphyschem 2024; 25:e202400277. [PMID: 38606486 DOI: 10.1002/cphc.202400277] [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: 03/12/2024] [Revised: 04/10/2024] [Accepted: 04/10/2024] [Indexed: 04/13/2024]
Abstract
The electronic origins of the computed optical rotations of the simplest chiral and achiral chemical knots with comparatively simple compositions and large, anticipated magnetoelectric polarizabilities are provided. Linear response theory (LRT) is used to calculate the gyration at 1064 nm of two knotted polyyne chains, topological stereoisomers of cyclo[60]carbon. One isomer is analogous to the trefoil knot with approximate D3 symmetry and the other to the figure eight knot with approximate S4 symmetry. The response in each case can be attributed largely to the magnetic dipole term that arises in a near degenerate E-like excited state. An oriented achiral figure eight knot is as optically active in some directions as the chiral knot in any direction, and its absolute eigenvalues are larger.
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Affiliation(s)
- Afton Gustafson
- Department of Chemistry and Molecular Design Institute, New York University, 100 Washington Square East, Room 1001, New York City, New York, 10003, USA
| | - Sophia Sburlati
- Department of Chemistry and Molecular Design Institute, New York University, 100 Washington Square East, Room 1001, New York City, New York, 10003, USA
| | - Bart Kahr
- Department of Chemistry and Molecular Design Institute, New York University, 100 Washington Square East, Room 1001, New York City, New York, 10003, USA
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21
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Mummaneni BC, Chen S, Hübner W, Lefkidis G. Investigation of the exact spin channels in laser-induced spin dynamics in two mononuclear Cu(II) complexes. Phys Chem Chem Phys 2024; 26:18816-18827. [PMID: 38940727 DOI: 10.1039/d4cp01086h] [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
In the quest to harness the potential of nanospintronic applications, we analyze and investigate the spin channels for the ultrafast spin dynamics in mononuclear Cu2+(tdp)Cl2 (Cutdp) and Cu2+(tdp)Cl2·MeCN (Cutdp·MeCN) using a high-level ab initio many-body theory. In that spirit, we select two slightly different polymerizations arising from one parent complex. We establish the difference in magnetic behavior between the two complexes which arises solely from the geometrical differences. We calculate the static magnetic properties, such as the magnetic anisotropy of the complexes, which is analyzed by means of the magnetic moment of the ground state. The asymmetry of the core Cu-Cl-Cu-Cl axial plane unit is also reflected in the ground state absorption spectra of the two complexes. Comparisons with the experimental data are in good agreement with the exception of one peak in the theoretical calculations for each of the complexes, confirming the reliability of theoretical methods employed. A major finding in this work is the distinction between classical and coherent superpositions of Λ processes. We employ the selective blocking and retention (SBR) technique to find the unique path or paths for spin dynamic scenarios like spin flip and spin transfer. Additionally, we also present two different scenarios in which intermediate states are involved in spin dynamic processes, (i) classical superposition of Λ processes (i.e., there are many unique paths for transition, even with just one intermediate state the transition completes successfully), and (ii) collective coherent superposition of Λ processes (i.e., there is only one path for the transition, which requires more than one intermediate state to be in a specific coherent superposition). As a consequence, we gain insight into the type of correlations (static or dynamic) involved in a particular spin dynamic scenario.
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Affiliation(s)
- Bharadwaj Chowdary Mummaneni
- Quantum Computing Group, Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO, Nobelstraße 12, 70569 Stuttgart, Germany
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, PO Box 3049, 67653 Kaiserslautern, Germany.
| | - Sihuai Chen
- Key Laboratory for Green Chemistry Process of Ministry of Education, School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430073, Peoples Republic of China
| | - Wolfgang Hübner
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, PO Box 3049, 67653 Kaiserslautern, Germany.
| | - Georgios Lefkidis
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, PO Box 3049, 67653 Kaiserslautern, Germany.
- School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi'an 710072, China
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22
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Choudhury A, Santra S, Ghosh D. Understanding the Photoprocesses in Biological Systems: Need for Accurate Multireference Treatment. J Chem Theory Comput 2024; 20:4951-4964. [PMID: 38864715 DOI: 10.1021/acs.jctc.4c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Light-matter interaction is crucial to life itself and revolves around many of the central processes in biology. The need for understanding these photochemical and photophysical processes cannot be overemphasized. Interaction of light with biological systems starts with the absorption of light and subsequent phenomena that occur in the excited states of the system. However, excited states are typically difficult to understand within the mean field approximation of quantum chemical methods. Therefore, suitable multireference methods and methodologies have been developed to understand these phenomena. In this Perspective, we will describe a few methods and methodologies suitable for these descriptions and discuss some persisting difficulties.
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Affiliation(s)
- Arpan Choudhury
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Supriyo Santra
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Debashree Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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23
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Alessio M, Paran GP, Utku C, Grüneis A, Jagau TC. Coupled-cluster treatment of complex open-shell systems: the case of single-molecule magnets. Phys Chem Chem Phys 2024; 26:17028-17041. [PMID: 38836327 PMCID: PMC11186456 DOI: 10.1039/d4cp01129e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/22/2024] [Indexed: 06/06/2024]
Abstract
We investigate the reliability of two cost-effective coupled-cluster methods for computing spin-state energetics and spin-related properties of a set of open-shell transition-metal complexes. Specifically, we employ the second-order approximate coupled-cluster singles and doubles (CC2) method and projection-based embedding that combines equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) with density functional theory (DFT). The performance of CC2 and EOM-CCSD-in-DFT is assessed against EOM-CCSD. The chosen test set includes two hexaaqua transition-metal complexes containing Fe(II) and Fe(III), and a large Co(II)-based single-molecule magnet with a non-aufbau ground state. We find that CC2 describes the excited states more accurately, reproducing EOM-CCSD excitation energies within 0.05 eV. However, EOM-CCSD-in-DFT excels in describing transition orbital angular momenta and spin-orbit couplings. Moreover, for the Co(II) molecular magnet, using EOM-CCSD-in-DFT eigenstates and spin-orbit couplings, we compute spin-reversal energy barriers, as well as temperature-dependent and field-dependent magnetizations and magnetic susceptibilities that closely match experimental values within spectroscopic accuracy. These results underscore the efficiency of CC2 in computing state energies of multi-configurational, open-shell systems and highlight the utility of the more cost-efficient EOM-CCSD-in-DFT for computing spin-orbit couplings and magnetic properties of complex and large molecular magnets.
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Affiliation(s)
- Maristella Alessio
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
- Institute for Theoretical Physics, TU Wien, Wiedner Hauptstraße 8-10/136, 1040 Vienna, Austria
| | | | - Cansu Utku
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
| | - Andreas Grüneis
- Institute for Theoretical Physics, TU Wien, Wiedner Hauptstraße 8-10/136, 1040 Vienna, Austria
| | - Thomas-C Jagau
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
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24
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Domingos SR, Tikhonov DS, Steber AL, Eschenbach P, Gruet S, Hrodmarsson HR, Martin K, Garcia GA, Nahon L, Neugebauer J, Avarvari N, Schnell M. Evolution of the ionisation energy with the stepwise growth of chiral clusters of [4]helicene. Nat Commun 2024; 15:4928. [PMID: 38858352 PMCID: PMC11164862 DOI: 10.1038/s41467-024-48778-0] [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: 09/19/2023] [Accepted: 05/13/2024] [Indexed: 06/12/2024] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are widely established as ubiquitous in the interstellar medium (ISM), but considering their prevalence in harsh vacuum environments, the role of ionisation in the formation of PAH clusters is poorly understood, particularly if a chirality-dependent aggregation route is considered. Here we report on photoelectron spectroscopy experiments on [4]helicene clusters performed with a vacuum ultraviolet synchrotron beamline. Aggregates (up to the heptamer) of [4]helicene, the smallest PAH with helical chirality, were produced and investigated with a combined experimental and theoretical approach using several state-of-the-art quantum-chemical methodologies. The ionisation onsets are extracted for each cluster size from the mass-selected photoelectron spectra and compared with calculations of vertical ionisation energies. We explore the complex aggregation topologies emerging from the multitude of isomers formed through clustering of P and M, the two enantiomers of [4]helicene. The very satisfactory benchmarking between experimental ionisation onsets vs. predicted ionisation energies allows the identification of theoretically predicted potential aggregation motifs and corresponding energetic ordering of chiral clusters. Our structural models suggest that a homochiral aggregation route is energetically favoured over heterochiral arrangements with increasing cluster size, hinting at potential symmetry breaking in PAH cluster formation at the scale of small grains.
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Affiliation(s)
- Sérgio R Domingos
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
- CFisUC, Department of Physics, University of Coimbra, 3004-516, Coimbra, Portugal.
| | - Denis S Tikhonov
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
| | - Amanda L Steber
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
- Department of Physical Chemistry, Faculty of Science, University of Valladolid, 47011, Valladolid, Spain.
| | - Patrick Eschenbach
- Organisch-Chemisches Institut, University of Münster, 48149, Münster, Germany
- Center for Multiscale Theory and Computation (CMTC), University of Münster, 48149, Münster, Germany
| | - Sebastien Gruet
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Helgi R Hrodmarsson
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif sur Yvette, Cedex, France
- 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
| | - Kévin Martin
- Univ Angers, CNRS, MOLTECH-Anjou, SFR MATRIX, 49000, Angers, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif sur Yvette, Cedex, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192, Gif sur Yvette, Cedex, France
| | - Johannes Neugebauer
- Organisch-Chemisches Institut, University of Münster, 48149, Münster, Germany
- Center for Multiscale Theory and Computation (CMTC), University of Münster, 48149, Münster, Germany
| | - Narcis Avarvari
- Univ Angers, CNRS, MOLTECH-Anjou, SFR MATRIX, 49000, Angers, France
| | - Melanie Schnell
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany.
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25
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Jangid B, Hermes MR, Gagliardi L. Core Binding Energy Calculations: A Scalable Approach with the Quantum Embedding-Based Equation-of-Motion Coupled-Cluster Method. J Phys Chem Lett 2024; 15:5954-5963. [PMID: 38810243 DOI: 10.1021/acs.jpclett.4c00957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
We investigated the use of density matrix embedding theory to facilitate the computation of core ionization energies (IPs) of large molecules at the equation-of-motion coupled-cluster singles doubles with perturbative triples (EOM-CCSD*) level in combination with the core-valence separation (CVS) approximation. The unembedded IP-CVS-EOM-CCSD* method with a triple-ζ basis set produced ionization energies within 1 eV of experiment with a standard deviation of ∼0.2 eV for the core65 data set. The embedded variant contributed very little systematic error relative to the unembedded method, with a mean unsigned error of 0.07 eV and a standard deviation of ∼0.1 eV, in exchange for accelerating the calculations by many orders of magnitude. By employing embedded EOM-CC methods, we computed the core ionization energies of the uracil hexamer, doped fullerene, and chlorophyll molecule, utilizing up to ∼4000 basis functions within 1 eV from experimental values. Such calculations are not currently possible with the unembedded EOM-CC method.
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Affiliation(s)
- Bhavnesh Jangid
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Matthew R Hermes
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Laura Gagliardi
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
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26
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Barhoumi M, Liu J, Hübner W, Lefkidis G. Using single and double laser pulses on the molecular Ni 4@C 48H 36 system to design integrated nanospintronic units. Phys Chem Chem Phys 2024; 26:16070-16090. [PMID: 38780108 DOI: 10.1039/d4cp00523f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The accomplishment of long-distance spin transfer scenarios between several magnetic centers is a big challenge for building and supporting spin-logic units for developing future all-optical magnetic unit operations. Using high-level quantum chemistry theory CCSD and EOM-CCSD, we systematically study the ultrafast laser-induced spin-dynamics process on a carbon-based material, to which four magnetic centers are attached. We show that the CCSD method with the 6-31G basis set calculation is sensitive to the C-Ni bond length. The spin density distribution, which is computed using EOM-CCSD with LanL2DZ+ECP calculations, Mulliken population analysis, including spin-orbit-coupling (SOC) and a magnetic field, fulfills the requirements for achieving spin dynamics processes. Different local spin-flip and spin-transfer processes are accomplished within the subpicosecond regime. The impact of the propagation direction of the laser pulse by switching their polar and the azimuthal angles in spherical coordinates on the spin dynamics processes is analyzed. Double laser pulses with time delay δt ≥ 200 × FWHM yield in a realistic magnetic field gradient selectively a lateral resolution, which corresponds to distances smaller than the CMOS scale (2 nm in 2024) while our system size is comparable to the CMOS scale. Here Λ and V processes with two quasi-degenerate intermediate levels are used. We propose a model of an integrated spin-logic processor created from an array of individual spin-logic blocks, which are realized by four magnetic centers Ni. The findings of this study demonstrate the enormous potential of using laser-induced spin dynamics as the fundamental mechanism for future molecular magnetic technology.
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Affiliation(s)
- Mohamed Barhoumi
- Deutsche Telekom Chair of Communication Networks, Institute of Communication Technology, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Dresden, Germany
- Quantum Communication Networks (QCNets) Research Group, Institute of Communication Technology, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Dresden, Germany
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
| | - Jing Liu
- Institute of Theoretical Chemistry, Ulm University, 89081 Ulm, Germany
| | - Wolfgang Hübner
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
| | - Georgios Lefkidis
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
- Department of Engineering Mechanics, Northwestern Polytechnical University, 710072 Xi'an, China
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27
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Khvorost T, Wójcik P, Chang C, Calvillo M, Dickerson C, Lao G, Hudson ER, Krylov AI, Alexandrova AN. Dual Optical Cycling Centers Mounted on an Organic Scaffold: New Insights from Quantum Chemistry Calculations and Symmetry Analysis. J Phys Chem Lett 2024; 15:5665-5673. [PMID: 38767654 DOI: 10.1021/acs.jpclett.4c00623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Molecules cooled to ultracold temperatures are desirable for applications in fundamental physics and quantum information science. However, cooling polyatomic molecules with more than six atoms has not yet been achieved. Building on the idea of an optical cycling center (OCC), a moiety supporting a set of localized and isolated electronic states within a polyatomic molecule, molecules with two OCCs (bi-OCCs) may afford better cooling efficiency by doubling the photon scattering rate. By using quantum chemistry calculations, we assess the extent of the coupling of the two OCCs with each other and the molecular scaffold. We show that promising coolable bi-OCC molecules can be proposed by following chemical design principles.
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Affiliation(s)
- Taras Khvorost
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Paweł Wójcik
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Cecilia Chang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Mia Calvillo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Claire Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Guanming Lao
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
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28
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Gałyńska M, Boguslawski K. Benchmarking Ionization Potentials from pCCD Tailored Coupled Cluster Models. J Chem Theory Comput 2024; 20:4182-4195. [PMID: 38752491 PMCID: PMC11137826 DOI: 10.1021/acs.jctc.4c00172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/29/2024]
Abstract
The ionization potential (IP) is an important parameter providing essential insights into the reactivity of chemical systems. IPs are also crucial for designing, optimizing, and understanding the functionality of modern technological devices. We recently showed that limiting the CC ansatz to the seniority-zero sector proves insufficient in predicting reliable and accurate ionization potentials within an IP equation-of-motion coupled-cluster formalism. Specifically, the absence of dynamical correlation in the seniority-zero pair coupled cluster doubles (pCCD) model led to unacceptably significant errors of approximately 1.5 eV. In this work, we aim to explore the impact of dynamical correlation and the choice of the molecular orbital basis (canonical vs localized) in CC-type methods targeting 230 ionized states in 70 molecules, comprising small organic molecules, medium-sized organic acceptors, and nucleobases. We focus on pCCD-based approaches as well as the conventional IP-EOM-CCD and IP-EOM-CCSD. Their performance is compared to the CCSD(T) or CCSDT equivalent and experimental reference data. Our statistical analysis reveals that all investigated frozen-pair coupled cluster methods exhibit similar performance, with differences in errors typically within chemical accuracy (1 kcal/mol or 0.05 eV). Notably, the effect of the molecular orbital basis, such as canonical Hartree-Fock or natural pCCD-optimized orbitals, on the IPs is marginal if dynamical correlation is accounted for. Our study suggests that triple excitations are crucial in achieving chemical accuracy in IPs when modeling electron detachment processes with pCCD-based methods.
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Affiliation(s)
- Marta Gałyńska
- Institute of Physics, Faculty of Physics,
Astronomy, and Informatics, Nicolaus Copernicus
University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
| | - Katharina Boguslawski
- Institute of Physics, Faculty of Physics,
Astronomy, and Informatics, Nicolaus Copernicus
University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
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29
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Li C, Mao S, Huang R, Evangelista FA. Frozen Natural Orbitals for the State-Averaged Driven Similarity Renormalization Group. J Chem Theory Comput 2024; 20:4170-4181. [PMID: 38747709 DOI: 10.1021/acs.jctc.4c00152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
We present a reduced-cost implementation of the state-averaged driven similarity renormalization group (SA-DSRG) based on the frozen natural orbital (FNO) approach. The natural orbitals (NOs) are obtained by diagonalizing the one-body reduced density matrix from SA-DSRG second-order perturbation theory (SA-DSRG-PT2). We consider three criteria to truncate the virtual NOs for the subsequent electron correlation treatment beyond SA-DSRG-PT2. An additive second-order correction is applied to the SA-DSRG Hamiltonian to reintroduce correlation effects from the discarded orbitals. The FNO SA-DSRG method is benchmarked on 35 small organic molecules in the QUEST database. When keeping 98-99% of the cumulative occupation numbers, the mean absolute error in the vertical transition energies due to FNO is less than 0.01 eV. Using the same FNO threshold, we observe a speedup of 9 times compared to the conventional SA-DSRG implementation for nickel carbonyl with a quadruple-ζ basis set. The FNO approach enables nonperturbative SA-DSRG computations on chloroiron corrole [FeCl(C19H11N4)] with more than 1000 basis functions, surpassing the current limit of a conventional implementation.
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Affiliation(s)
- Chenyang Li
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Shuxian Mao
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Renke Huang
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Francesco A Evangelista
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
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30
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Skrzyński G, Musial M. An Intruder-Free Fock Space Coupled-Cluster Study of the Potential Energy Curves of LiMg + within the (2,0) Sector. Molecules 2024; 29:2364. [PMID: 38792225 PMCID: PMC11124300 DOI: 10.3390/molecules29102364] [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: 04/18/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
The potential energy curves (PECs) and spectroscopic constants of the ground and excited states of a LiMg+ molecular cation were investigated. We obtained accurate results for the fifteen lowest-lying states of the LiMg+ cation using the Intermediate Hamiltonian Fock Space Multireference Coupled Cluster (IH-FS-CC) method applied to the (2,0) sector. Relativistic corrections were accounted for using the third-order Douglas-Kroll method. In each instance, smooth PECs were successfully computed across the entire range of interatomic distances from equilibrium to the dissociation limit. The results are in good accordance with previous studies of this molecular cation. Notably, this study marks the first application of IH-FS-CC in investigating a mixed alkali and alkaline earth molecular cation, proving its usability in determining accurate PECs of such diatomics and their spectroscopic constants.
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Affiliation(s)
- Grzegorz Skrzyński
- Institute of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
| | - Monika Musial
- Institute of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
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31
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Elayan IA, Rib L, A Mendes R, Brown A. Beyond Explored Functionals: A Computational Journey of Two-Photon Absorption. J Chem Theory Comput 2024; 20:3879-3893. [PMID: 38648613 DOI: 10.1021/acs.jctc.4c00133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
We present a thorough investigation into the efficacy of 19 density functional theory (DFT) functionals, relative to RI-CC2 results, for computing two-photon absorption (2PA) cross sections (σ2PA) and key dipole moments (|μ00|, |μ11|, |Δμ|, |μ01|) for a series of coumarin dyes in the gas-phase. The functionals include different categories, including local density approximation (LDA), generalized gradient approximation (GGA), hybrid-GGA (H-GGA), range-separated hybrid-GGA (RSH-GGA), meta-GGA (M-GGA), and hybrid M-GGA (HM-GGA), with 14 of them being subjected to analysis for the first time with respect to predicting σ2PA values. Analysis reveals that functionals integrating both short-range (SR) and long-range (LR) corrections, particularly those within the RSH-GGA and HM-GGA classes, outperform the others. Furthermore, the range-separation approach was found more impactful compared to the varying percentages of Hartree-Fock exchange (HF Ex) within different functionals. The functionals traditionally recommended for 2PA do not appear among the top 9 in our study, which is particularly interesting, as these top-performing functionals have not been previously investigated in this context. This list is dominated by M11, QTP variants, ωB97X, ωB97X-V, and M06-2X, surpassing the performance of other functionals, including the commonly used CAM-B3LYP.
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Affiliation(s)
- Ismael A Elayan
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Laura Rib
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Rodrigo A Mendes
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Departamento de Química, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil
| | - Alex Brown
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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32
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Sarangi R, Nanda KD, Krylov AI. Two- and one-photon absorption spectra of aqueous thiocyanate anion highlight the role of symmetry in the condensed phase. J Comput Chem 2024; 45:878-885. [PMID: 38156823 DOI: 10.1002/jcc.27282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/22/2023] [Accepted: 11/25/2023] [Indexed: 01/03/2024]
Abstract
We present the two-photon absorption (2PA) spectrum of aqueous thiocyanate calculated using high-level quantum-chemistry methods. The 2PA spectrum is compared to the one-photon absorption (1PA) spectrum computed using the same computational protocol. Although the two spectra probe the same set of electronic states, the intensity patterns are different, leading to an apparent red-shift of the 2PA spectrum relative to the 1PA spectrum. The presented analysis explains the intensity patterns and attributes the differences between the 1PA and 2PA spectra to the native symmetry of isolated SCN - , which influences the spectra in the low-symmetry solvated environment. The native symmetry also manifests itself in variations of the polarization ratio (e.g., parallel vs. perpendicular cross sections) across the spectrum. The presented results highlight the potential of 2PA spectroscopy and high-level quantum-chemistry methods in studies of condensed-phase phenomena.
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Affiliation(s)
- Ronit Sarangi
- Department of Chemistry, University of Southern California, Los Angeles, California, USA
| | - Kaushik D Nanda
- Department of Chemistry, University of Southern California, Los Angeles, California, USA
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California, USA
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33
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Hunter KE, Mao Y, Chin AW, Zuehlsdorff TJ. Environmentally Driven Symmetry Breaking Quenches Dual Fluorescence in Proflavine. J Phys Chem Lett 2024; 15:4623-4632. [PMID: 38647005 DOI: 10.1021/acs.jpclett.4c00677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Nonadiabatic couplings between several electronic excited states are ubiquitous in many organic chromophores and can significantly influence optical properties. A recent experimental study demonstrated that the proflavine molecule exhibits surprising dual fluorescence in the gas phase, which is suppressed in polar solvent environments. Here, we uncover the origin of this phenomenon by parametrizing a linear-vibronic coupling Hamiltonian from spectral densities of system-bath coupling constructed along molecular dynamics trajectories, fully accounting for interactions with the condensed-phase environment. The finite-temperature absorption, steady-state emission, and time-resolved emission spectra are then computed using powerful, numerically exact tensor network approaches. We find that the dual fluorescence in vacuum is driven by a single well-defined coupling mode but is quenched in solution due to dynamic solvent-driven symmetry breaking that mixes the two low-lying electronic states. We expect the computational framework developed here to be widely applicable to the study of non-Condon effects in complex condensed-phase environments.
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Affiliation(s)
- Kye E Hunter
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Yuezhi Mao
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182, United States
| | - Alex W Chin
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, 4 place Jussieu, Paris 75005, France
| | - Tim J Zuehlsdorff
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
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34
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Zhang T, Banerjee S, Koulias LN, Valeev EF, DePrince AE, Li X. Dirac-Coulomb-Breit Molecular Mean-Field Exact-Two-Component Relativistic Equation-of-Motion Coupled-Cluster Theory. J Phys Chem A 2024; 128:3408-3418. [PMID: 38651293 DOI: 10.1021/acs.jpca.3c08167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
We present a relativistic equation-of-motion coupled-cluster with single and double excitation formalism within the exact two-component framework (X2C-EOM-CCSD), where both scalar relativistic effects and spin-orbit coupling are variationally included at the reference level. Three different molecular mean-field treatments of relativistic corrections, including the one-electron, Dirac-Coulomb, and Dirac-Coulomb-Breit Hamiltonian, are considered in this work. Benchmark calculations include atomic excitations and fine-structure splittings arising from spin-orbit coupling. Comparison with experimental values and relativistic time-dependent density functional theory is also carried out. The computation of the oscillator strength using the relativistic X2C-EOM-CCSD approach allows for studies of spin-orbit-driven processes, such as the spontaneous phosphorescence lifetime.
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Affiliation(s)
- Tianyuan Zhang
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Samragni Banerjee
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Lauren N Koulias
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Edward F Valeev
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - A Eugene DePrince
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Xiaosong Li
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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35
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Wen M, Abraham V, Harsha G, Shee A, Whaley KB, Zgid D. Comparing Self-Consistent GW and Vertex-Corrected G0W0 ( G0W0Γ) Accuracy for Molecular Ionization Potentials. J Chem Theory Comput 2024; 20:3109-3120. [PMID: 38573104 DOI: 10.1021/acs.jctc.3c01279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
We test the performance of self-consistent GW and several representative implementations of vertex-corrected G0W0 (G0W0Γ). These approaches are tested on benchmark data sets covering full valence spectra (first ionization potentials and some inner valence shell excitations). For small molecules, when comparing against state-of-the-art wave function techniques, our results show that full self-consistency in the GW scheme either systematically outperforms vertex-corrected G0W0 or gives results of at least comparative quality. Moreover, G0W0Γ results in additional computational cost when compared to G0W0 or self-consistent GW. The dependency of G0W0Γ on the starting mean-field solution is frequently more dominant than the magnitude of the vertex correction itself. Consequently, for molecular systems, self-consistent GW performed on the imaginary axis (and then followed by modern analytical continuation techniques) offers a more reliable approach to make predictions of ionization potentials.
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Affiliation(s)
- Ming Wen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Vibin Abraham
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Gaurav Harsha
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Avijit Shee
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - K Birgitta Whaley
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
| | - Dominika Zgid
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
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36
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Toboła R. Reasons Why Most Single-Reference Coupled Cluster Methods Fail to Provide the Correct Adiabatic Potentials of a Diatomic Carbon Molecule: UCCSDecCCSD Potential Study. J Phys Chem A 2024; 128:3033-3046. [PMID: 38590009 DOI: 10.1021/acs.jpca.4c00565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Many single-reference coupled cluster (CC) methods offer adiabatically incorrect potentials when calculating the diatomic carbon molecule, so this problem has been studied extensively. Analysis of the full configuration interaction (FCI) wave function indicates that the main cause of the adiabatic collapse of potentials calculated by the CC method with singles, doubles, and triples (CCSDT) is the strongly increasing bonding character of the T4FCI cluster contribution. In turn, comparative analysis of the CCSDTQ adiabats X1Σg+ and B'1Σg+ demonstrates that the gap between them near the avoided crossing geometry is significantly reduced by quantitatively differentiating the character of the T4 and T 4 B ' 1 Σ g + cluster contributions. These observations clearly indicate the need to take into account the T4 cluster contribution in the standard CC wave function to obtain the correct adiabatic potential. Further analysis of this issue shows that the T4 contribution must be additionally bonding to ensure the adiabatic correctness of the potential. What also seems very interesting is that when the UCCSDecCCSD method [Toboła, Chem. Phys. Lett. 2014, 614, 82-88] is used for the potential calculation, the shape of the potential is entirely determined by a subset of unrestricted Hartree-Fock (UHF) configurations, which are structurally identical to the ground-state configuration in the UHF-based CCSD wave function.
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Affiliation(s)
- Robert Toboła
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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37
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Izu AE, Matxain JM, Casanova D. Reverse intersystem crossing mechanisms in doped triangulenes. Phys Chem Chem Phys 2024; 26:11459-11468. [PMID: 38563957 DOI: 10.1039/d4cp00304g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Thermally activated delayed fluorescence (TADF) has emerged as one of the most promising strategies in the quest for organic light emitting diodes with optimal performance. This computational study dissects the mechanistic intricacies of the central photophysical step, reverse intersystem crossing (rISC) in N and B doped triangulenes as potential multi-resonance TADF compounds. Optimal molecular patterns conducive to efficient rISC, encompassing dopant atom size, number, and distribution, are identified. Additionally, we assess various electronic structure methods for characterizing TADF-relevant molecular systems. The findings identify the distinct role of the direct and mediated mechanisms in rISC, and provide insights into the design of advanced TADF chromophores for next-generation OLED technology.
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Affiliation(s)
- Asier E Izu
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia Saila, Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), PK 1072, 20080 Donostia, Euskadi, Spain
| | - Jon M Matxain
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia Saila, Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), PK 1072, 20080 Donostia, Euskadi, Spain
| | - David Casanova
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Euskadi, Spain
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38
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Tuckman H, Neuscamman E. Aufbau Suppressed Coupled Cluster Theory for Electronically Excited States. J Chem Theory Comput 2024; 20:2761-2773. [PMID: 38502102 DOI: 10.1021/acs.jctc.3c01285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
We introduce an approach to improve single-reference coupled cluster theory in settings where the Aufbau determinant is absent from or plays only a small role in the true wave function. Using a de-excitation operator that can be efficiently hidden within a similarity transform, we create a coupled cluster wave function in which de-excitations work to suppress the Aufbau determinant and produce wave functions dominated by other determinants. Thanks to an invertible and fully exponential form, the approach is systematically improvable, size consistent, size extensive, and, interestingly, size intensive in a granular way that should make the adoption of some ground state techniques, such as local correlation, relatively straightforward. In this initial study, we apply the general formalism to create a state-specific method for orbital-relaxed, singly excited states. We find that this approach matches the accuracy of similar-cost equation-of-motion methods in valence excitations while offering improved accuracy for charge transfer states. We also find the approach to be more accurate than excited-state-specific perturbation theory in both types of states.
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Affiliation(s)
- Harrison Tuckman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eric Neuscamman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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39
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Haggag O, Baer R, Ruhman S, Krylov AI. Revisiting the benzene excimer using [2,2] paracyclophane model system: Experiment and theory. J Chem Phys 2024; 160:124111. [PMID: 38530011 DOI: 10.1063/5.0196641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/06/2024] [Indexed: 03/27/2024] Open
Abstract
We report high-level calculations of the excited states of [2,2]-paracyclophane (PCP), which was recently investigated experimentally by ultrafast pump-probe experiments on oriented single crystals [Haggag et al., ChemPhotoChem 6 e202200181 (2022)]. PCP, in which the orientation of the two benzene rings and their range of motion are constrained, serves as a model for studying benzene excimer formation. The character of the excimer state and the state responsible for the brightest transition are similar to those of the benzene dimer. The constrained structure of PCP allows one to focus on the most important degree of freedom, the inter-ring distance. The calculations explain the main features of the transient absorption spectral evolution. This brightest transition of the excimer is polarized along the inter-fragment axis. The absorption of the light polarized in the plane of the rings reveals the presence of other absorbing states of Rydberg character, with much weaker intensities. We also report new transient absorption data obtained by a broadband 8 fs pump, which time-resolve strong modulations of the excimer absorption. The combination of theory and experiment provides a detailed picture of the evolution of the electronic structure of the PCP excimer in the course of a single molecular vibration.
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Affiliation(s)
- Omer Haggag
- Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Roi Baer
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Sanford Ruhman
- Institute of Chemistry, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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40
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Patra A, Pipim GB, Krylov AI, Mallikarjun Sharada S. Performance of Density Functionals for Excited-State Properties of Isolated Chromophores and Exciplexes: Emission Spectra, Solvatochromic Shifts, and Charge-Transfer Character. J Chem Theory Comput 2024; 20:2520-2537. [PMID: 38488640 DOI: 10.1021/acs.jctc.4c00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
This study assesses the performance of various meta-generalized gradient approximation (meta-GGA), global hybrid, and range-separated hybrid (RSH) density functionals in capturing the excited-state properties of organic chromophores and their excited-state complexes (exciplexes). Motivated by their uses in solar energy harvesting and photoredox CO2 reduction, we use oligo-(p-phenylenes) and their excited-state complexes with triethylamine as model systems. We focus on the fluorescence properties of these systems, specifically emission energies. We also consider solvatochromic shifts and wave function characteristics. The latter is described by using reduced quantities such as natural transition orbitals (NTOs) and exciton descriptors. The functionals are benchmarked against the experimental fluorescence spectra and the equation-of-motion coupled-cluster method with single and double excitations. Both in isolated chromophores and in exciplexes, meta-GGA functionals drastically underestimate the emission energies and exhibit significant exciton delocalization and anticorrelation between electron and hole motion. The performance of global hybrid functionals is strongly dependent on the percentage of exact exchange. Our study identifies RSH GGAs as the best-performing functionals, with ωPBE demonstrating the best agreement with experimental results. RSH meta-GGAs often overestimate emission energies in exciplexes and yield larger hole NTOs. Their performance can be improved by optimally tuning the range-separation parameter.
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Affiliation(s)
- Abhilash Patra
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - George Baffour Pipim
- Department of Chemistry, University of Southern California, Los Angeles ,California 90089, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles ,California 90089, United States
| | - Shaama Mallikarjun Sharada
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
- Department of Chemistry, University of Southern California, Los Angeles ,California 90089, United States
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41
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Watrous AG, Davis MC, Fortenberry RC. Performance of EOM-CCSD(T)(a)*-Based Quartic Force Fields in Computing Fundamental, Anharmonic Vibrational Frequencies of Molecular Electronically Excited States with Application to the Ã1A″ State of :CCH 2 (Vinylidene). J Phys Chem A 2024; 128:2150-2161. [PMID: 38466814 DOI: 10.1021/acs.jpca.3c08168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Highly accurate anharmonic vibrational frequencies of electronically excited states are not as easily computed as their ground electronic state counterparts, but recently developed approximate triple excited state methods may be changing that. One emerging excited state method is equation of motion coupled cluster theory at the singles and doubles level with perturbative triples computed via the (a)* formalism, EOMEE-CCSD(T)(a)*. One of the most employed means for the ready computation of vibrational anharmonic frequencies for ground electronic states is second-order vibrational perturbation theory (VPT2), a theory based on quartic force fields (QFFs),fourth-order Taylor series expansions of the potential portion of the internuclear Watson Hamiltonian. The combination of these two is herein benchmarked for its performance for use as a means of computing rovibrational spectra of electronically excited states. Specifically, the EOMEE-CCSD(T)(a)* approach employing a complete basis set extrapolation along with core electron inclusion and relativity (the so-called "CcCR" approach) defining the QFF produces anharmonic fundamental vibrational frequencies within 2.83%, on the average, of reported gas-phase experimentally assigned values for the test set including the A ~ 1 A ″ states of HCF, HCCl, HSiF, HNO, and HPO. However, some states have exceptional accuracy in the fundamentals, most notably for ν2 of A ~ 1 A ″ HCCl in which the CcCR QFF value is within 1.8 cm-1 at 927.9 cm-1 (or 0.2%) of the experiment. Additionally, this approach produces rotational constants to, on the absolute average, within 0.41% of available experimental data, showcasing notable accuracy in the computation of rovibronic spectral data. Furthermore, utilizing a hybrid approach composed of harmonic CcCR force constants along with a set of simple EOMEE-CCSD(T)(a)*/aug-cc-pVQZ QFF cubic and quartic force constants is faster than using pure CcCR and better represents those modes that suffer from numerical instability in the anharmonic portion of the QFF, implying that this so-called "CcCR + QZ" QFF approach may be the best for future applications. Finally, complete, rovibrational spectral data are provided for A ~ 1 A 2 :CCH2, a molecule of potential astrochemical interest, in order to aid in its potential future experimental rovibronic characterization.
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Affiliation(s)
- Alexandria G Watrous
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
| | - Megan C Davis
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
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42
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Lew-Yee JFH, Bonfil-Rivera IA, Piris M, M. del Campo J. Excited States by Coupling Piris Natural Orbital Functionals with the Extended Random-Phase Approximation. J Chem Theory Comput 2024; 20:2140-2151. [PMID: 38353418 PMCID: PMC10938499 DOI: 10.1021/acs.jctc.3c01194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 03/13/2024]
Abstract
In this work, we explore the use of Piris natural orbital functionals (PNOFs) to calculate excited-state energies by coupling their reconstructed second-order reduced density matrix with the extended random-phase approximation (ERPA). We have named the general method PNOF-ERPA, and specific approaches are referred to as PNOF-ERPA0, PNOF-ERPA1, and PNOF-ERPA2, according to the way the excitation operator is built. The implementation has been tested in the first excited states of H2, HeH+, LiH, Li2, and N2 showing good results compared to the configuration interaction (CI) method. As expected, an increase in accuracy is observed on going from ERPA0 to ERPA1 and ERPA2. We also studied the effect of electron correlation included by PNOF5, PNOF7, and the recently proposed global NOF (GNOF) on the predicted excited states. PNOF5 appears to be good and may even provide better results in very small systems, but including more electron correlation becomes important as the system size increases, where GNOF achieves better results. Overall, the extension of PNOF to excited states has been successful, making it a promising method for further applications.
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Affiliation(s)
- Juan Felipe Huan Lew-Yee
- Departamento
de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México City C.P.
04510, Mexico
- Donostia
International Physics Center (DIPC), 20018 Donostia, Spain
| | - Iván Alejandro Bonfil-Rivera
- Departamento
de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México City C.P.
04510, Mexico
| | - Mario Piris
- Donostia
International Physics Center (DIPC), 20018 Donostia, Spain
- Kimika
Fakultatea, Euskal Herriko Unibertsitatea
(UPV/EHU), 20018 Donostia, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Spain
| | - Jorge M. del Campo
- Departamento
de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México City C.P.
04510, Mexico
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43
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López Peña HA, Shusterman JM, Dalkiewicz C, McPherson SL, Dunstan C, Sangroula K, Lao KU, Tibbetts KM. Photodissociation Dynamics of the Highly Stable ortho-Nitroaniline Cation. J Phys Chem A 2024; 128:1634-1645. [PMID: 38411108 PMCID: PMC10926099 DOI: 10.1021/acs.jpca.3c08364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
0rtho-Nitroaniline (ONA) is a model for the insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) that shares strong hydrogen bonding character between adjacent nitro and amino groups. This work reports femtosecond time-resolved mass spectrometry (FTRMS) measurements and theoretical calculations that explain the high stability of the ONA cation compared with related nitroaromatic molecules. Ab initio calculations found that the lowest-lying electronic excited state of the ONA cation, D1, lies more than 2 eV above the ground state, and the energetic barriers to rearrangement and dissociation reactions exceed this D1 energy. These theoretical results were confirmed by FTRMS pump-probe measurements showing that (1) fragment ions represented less than 30% of the total ion yield when a 1014 W cm-2, 1300 nm, 20 fs pump pulse was used to ionize ONA; and (2) 3.1 eV (400 nm) photons were required to induce dissociation of the ONA cation. Stronger coupling between the ground D0 and excited D4 states of the ONA cation at the geometry of neutral ONA resulted in a transient enhancement of fragment ion yields at <300 fs pump-probe delay times, prior to relaxation of the ONA cation to its optimal geometry.
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Affiliation(s)
- Hugo A. López Peña
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Jacob M. Shusterman
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Clayton Dalkiewicz
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Shane L. McPherson
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Christine Dunstan
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Kunjal Sangroula
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Ka Un Lao
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Katharine Moore Tibbetts
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
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44
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Nigam A, Pollice R, Friederich P, Aspuru-Guzik A. Artificial design of organic emitters via a genetic algorithm enhanced by a deep neural network. Chem Sci 2024; 15:2618-2639. [PMID: 38362419 PMCID: PMC10866360 DOI: 10.1039/d3sc05306g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 01/10/2024] [Indexed: 02/17/2024] Open
Abstract
The design of molecules requires multi-objective optimizations in high-dimensional chemical space with often conflicting target properties. To navigate this space, classical workflows rely on the domain knowledge and creativity of human experts, which can be the bottleneck in high-throughput approaches. Herein, we present an artificial molecular design workflow relying on a genetic algorithm and a deep neural network to find a new family of organic emitters with inverted singlet-triplet gaps and appreciable fluorescence rates. We combine high-throughput virtual screening and inverse design infused with domain knowledge and artificial intelligence to accelerate molecular generation significantly. This enabled us to explore more than 800 000 potential emitter molecules and find more than 10 000 candidates estimated to have inverted singlet-triplet gaps (INVEST) and appreciable fluorescence rates, many of which likely emit blue light. This class of molecules has the potential to realize a new generation of organic light-emitting diodes.
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Affiliation(s)
- AkshatKumar Nigam
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto 80 St. George St Toronto Ontario M5S 3H6 Canada
- Department of Computer Science, University of Toronto 40 St. George St Toronto Ontario M5S 2E4 Canada
| | - Robert Pollice
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto 80 St. George St Toronto Ontario M5S 3H6 Canada
- Department of Computer Science, University of Toronto 40 St. George St Toronto Ontario M5S 2E4 Canada
| | - Pascal Friederich
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto 80 St. George St Toronto Ontario M5S 3H6 Canada
- Department of Computer Science, University of Toronto 40 St. George St Toronto Ontario M5S 2E4 Canada
- Institute of Nanotechnology, Karlsruhe Institute of Technology Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen Germany
- Institute of Theoretical Informatics, Karlsruhe Institute of Technology Am Fasanengarten 5 76131 Karlsruhe Germany
| | - Alán Aspuru-Guzik
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto 80 St. George St Toronto Ontario M5S 3H6 Canada
- Department of Computer Science, University of Toronto 40 St. George St Toronto Ontario M5S 2E4 Canada
- Vector Institute for Artificial Intelligence 661 University Ave Suite 710 Toronto Ontario M5G 1M1 Canada
- Department of Chemical Engineering & Applied Chemistry, University of Toronto 200 College St. Ontario M5S 3E5 Canada
- Department of Materials Science & Engineering, University of Toronto, 184 College St. Ontario M5S 3E4 Canada
- Lebovic Fellow, Canadian Institute for Advanced Research (CIFAR) 661 University Ave Toronto Ontario M5G Canada
- Acceleration Consortium Toronto Ontario M5G 3H6 Canada
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45
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Rutskoy B, Ozerov G, Bezrukov D. The Role of Bond Functions in Describing Intermolecular Electron Correlation for Van der Waals Dimers: A Study of (CH 4) 2 and Ne 2. Int J Mol Sci 2024; 25:1472. [PMID: 38338750 PMCID: PMC10855067 DOI: 10.3390/ijms25031472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
We present a study of the intermolecular interactions in van der Waals complexes of methane and neon dimers within the framework of the CCSD method. This approach was implemented and applied to calculate and examine the behavior of the contracted two-particle reduced density matrix (2-RDM). It was demonstrated that the region near the minimum of the two-particle density matrix correlation part, corresponding to the primary bulk of the Coulomb hole contribution, exerts a significant influence on the dispersion interaction energetics of the studied systems. As a result, the bond functions approach was applied to improve the convergence performance for the intermolecular correlation energy results with respect to the size of the atomic basis. For this, substantial acceleration was achieved by introducing an auxiliary basis of bond functions centered on the minima of the 2-RDM. For both methane and neon dimers, this general conclusion was confirmed with a series of CCSD calculations for the 2-RDM and the correlation energies.
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Affiliation(s)
- Bogdan Rutskoy
- National Research Centre “Kurchatov Institute”, Moscow 123182, Russia;
- Institute of Nuclear Physics and Technology, National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Moscow 115409, Russia
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow 119991, Russia;
| | - Georgiy Ozerov
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow 119991, Russia;
| | - Dmitry Bezrukov
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow 119991, Russia;
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46
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Dey D, Woodhouse JL, Taylor MP, Fielding HH, Worth GA. On the multiphoton ionisation photoelectron spectra of phenol. Phys Chem Chem Phys 2024; 26:3451-3461. [PMID: 38205824 DOI: 10.1039/d3cp05559k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The phenol molecule is a prototype for non-adiabatic dynamics and the excited-state photochemistry of biomolecules. In this article, we report a joint theoretical and experimental investigation on the resonance enhanced multiphoton ionisation photoelectron (REMPI) spectra of the two lowest ionisation bands of phenol. The focus is on the theoretical interpretation of the measured spectra using quantum dynamics simulations. These were performed by numerically solving the time-dependent Schrödinger equation using the multi-layer variant of the multiconfiguration time-dependent Hartree algorithm together with a vibronic coupling Hamiltonian model. The ionising laser pulse is modelled explicitly within the ionisation continuum model to simulate experimental femtosecond 1+1 REMPI photoelectron spectra. These measured spectra are sensitive to very short lived electronically excited states, providing a rigorous benchmark for our theoretical methods. The match between experiment and theory allows for an interpretation of the features of the spectra at different wavelengths and shows that there are features due to both 'direct' and 'indirect' ionisation, resulting from non-resonant and resonant excitation by the pump pulse.
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Affiliation(s)
- Diptesh Dey
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Joanne L Woodhouse
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Marcus P Taylor
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
| | - Helen H Fielding
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
| | - Graham A Worth
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
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47
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Arias-Martinez JE, Wu H, Head-Gordon M. Generalization of One-Center Nonorthogonal Configuration Interaction Singles to Open-Shell Singlet Reference States: Theory and Application to Valence-Core Pump-Probe States in Acetylacetone. J Chem Theory Comput 2024; 20:752-766. [PMID: 38164934 DOI: 10.1021/acs.jctc.3c01139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
We formulate a one-center nonorthogonal configuration interaction singles (1C-NOCIS) theory for the computation of core excited states of an initial singlet state with two unpaired electrons. This model, which we refer to as 1C-NOCIS two-electron open-shell (2eOS), is appropriate for computing the K-edge near-edge X-ray absorption spectra (NEXAS) of the valence excited states of closed-shell molecules relevant to pump-probe time-resolved (TR) NEXAS experiments. With the inclusion of core-hole relaxation effects and explicit spin adaptation, 1C-NOCIS 2eOS requires mild shifts to match experiment, is free of artifacts due to spin contamination, and can capture the high-energy region of the spectrum beyond the transitions into the singly occupied molecular orbitals (SOMOs). Calculations on water and thymine illustrate the different key features of excited-state NEXAS, namely, the core-to-SOMO transitions as well as shifts and spin-splittings in the transitions analogous to those of the ground state. Simulations of the TR-NEXAS of acetylacetone after excitation to its π → π* singlet excited state at the carbon K-edge, an experiment carried out recently, showcase the ability of 1C-NOCIS 2eOS to efficiently simulate NEXAS based on nonadiabatic molecular dynamics simulations.
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Affiliation(s)
- Juan E Arias-Martinez
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hamlin Wu
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Martin Head-Gordon
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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48
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Yuan X, Halbert L, Pototschnig JV, Papadopoulos A, Coriani S, Visscher L, Pereira Gomes AS. Formulation and Implementation of Frequency-Dependent Linear Response Properties with Relativistic Coupled Cluster Theory for GPU-Accelerated Computer Architectures. J Chem Theory Comput 2024; 20:677-694. [PMID: 38193434 DOI: 10.1021/acs.jctc.3c00812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
We present the development and implementation of relativistic coupled cluster linear response theory (CC-LR), which allows the determination of molecular properties arising from time-dependent or time-independent electric, magnetic, or mixed electric-magnetic perturbations (within a common gauge origin for the magnetic properties) as well as taking into account the finite lifetime of excited states in the framework of damped response theory. We showcase our implementation, which is capable to offload the computationally intensive tensor contractions characteristic of coupled cluster theory onto graphical processing units, in the calculation of (a) frequency-(in)dependent dipole-dipole polarizabilities of IIB atoms and selected diatomic molecules, with a particular emphasis on the calculation of valence absorption cross sections for the I2 molecule; (b) indirect spin-spin coupling constants for benchmark systems such as the hydrogen halides (HX, X = F-I) as well the H2Se-H2O dimer as a prototypical system containing hydrogen bonds; and (c) optical rotations at the sodium D line for hydrogen peroxide analogues (H2Y2, Y = O, S, Se, Te). Thanks to this implementation, we are able to show the similarities in performance, but often the significant discrepancies, between CC-LR and approximate methods such as density functional theory. Comparing standard CC response theory with the flavor based upon the equation of motion formalism, we find that for valence properties such as polarizabilities, the two frameworks yield very similar results across the periodic table as found elsewhere in the literature; for properties that probe the core region, such as spin-spin couplings, on the other hand, we show a progressive differentiation between the two as relativistic effects become more important. Our results also suggest that as one goes down the periodic table, it may become increasingly difficult to measure pure optical rotation at the sodium D line due to the appearance of absorbing states.
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Affiliation(s)
- Xiang Yuan
- Univ. Lille, CNRS, UMR 8523─PhLAM─Physique des Lasers Atomes et Molécules, F-59000 Lille, France
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Loïc Halbert
- Univ. Lille, CNRS, UMR 8523─PhLAM─Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Johann Valentin Pototschnig
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Anastasios Papadopoulos
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Sonia Coriani
- DTU Chemistry─Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Lucas Visscher
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
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49
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Zhang C, Lipparini F, Stopkowicz S, Gauss J, Cheng L. Cholesky Decomposition-Based Implementation of Relativistic Two-Component Coupled-Cluster Methods for Medium-Sized Molecules. J Chem Theory Comput 2024; 20:787-798. [PMID: 38198515 DOI: 10.1021/acs.jctc.3c01236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
A Cholesky decomposition (CD)-based implementation of relativistic two-component coupled-cluster (CC) and equation-of-motion CC (EOM-CC) methods using an exact two-component Hamiltonian augmented with atomic-mean-field spin-orbit integrals (the X2CAMF scheme) is reported. The present CD-based implementation of X2CAMF-CC and EOM-CC methods employs atomic-orbital-based algorithms to avoid the construction of two-electron integrals and intermediates involving three and four virtual indices. Our CD-based implementation extends the applicability of X2CAMF-CC and EOM-CC methods to medium-sized molecules with the possibility to correlate around 1000 spinors. Benchmark calculations for uranium-containing small molecules were performed to assess the dependence of the CC results on the Cholesky threshold. A Cholesky threshold of 10-4 is shown to be sufficient to maintain chemical accuracy. Example calculations to illustrate the capability of the CD-based relativistic CC methods are reported for the bond-dissociation energy of the uranium hexafluoride molecule, UF6, with up to quadruple-ζ basis sets, and the lowest excitation energy in the solvated uranyl ion [UO22+(H2O)12].
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, the Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Filippo Lipparini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, Pisa I-56124, Italy
| | - Stella Stopkowicz
- Fachrichtung Chemie, Universität des Saarlandes, Saarbrücken D-66123, Germany
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, Oslo N-0315, Norway
| | - Jürgen Gauss
- Department Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, Mainz D-55128, Germany
| | - Lan Cheng
- Department of Chemistry, the Johns Hopkins University, Baltimore, Maryland 21218, United States
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50
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Simons J. An environmental impact statement for molecular anions. Phys Chem Chem Phys 2024; 26:1564-1586. [PMID: 38126406 DOI: 10.1039/d3cp04842j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
A molecular anion's (MA's) chemical reactivity and physical behavior can be quite different when it is surrounded by other molecules than when it exists in isolation. This sensitivity to the surrounding environment is especially high for anions because their outermost valence electrons are typically loosely bound and exist in rather spatially diffuse orbitals, allowing even weak intermolecular interactions arising from the environment to have strong effects. This Perspective offers illustrations of such sensitivity for a variety of cases including (i) the effect of solvation on electron binding energies, (ii) how some "well known" anions need to have solvent molecules around to even exist as stable species, (iii) how internal Coulomb repulsions within a multiply charged MA can provide temporary stability toward electron loss, (iv) how MAs arrange themselves spatially near liquid/vapor interfaces in manners that can produce unusual reactivity, (v) how nearby cationic sites can facilitate electron attachment to form a MA site elsewhere, (vi) how internal vibrational or rotational energy can make a MA detach an electron.
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Affiliation(s)
- Jack Simons
- Henry Eyring Center for Theoretical Chemistry, Department of Chemistry, University of Utah, Salt Lake City, UT, 84112, USA.
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