1
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Myers CA, Lu SY, Shedge S, Pyuskulyan A, Donahoe K, Khanna A, Shi L, Isborn CM. Axial H-Bonding Solvent Controls Inhomogeneous Spectral Broadening, While Peripheral H-Bonding Solvent Controls Vibronic Broadening: Cresyl Violet in Methanol. J Phys Chem B 2024; 128:5685-5699. [PMID: 38832562 DOI: 10.1021/acs.jpcb.4c01401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The dynamics of the nuclei of both a chromophore and its condensed-phase environment control many spectral features, including the vibronic and inhomogeneous broadening present in spectral line shapes. For the cresyl violet chromophore in methanol, we here analyze and isolate the effect of specific chromophore-solvent interactions on simulated spectral densities, reorganization energies, and linear absorption spectra. Employing both chromophore and its condensed-phase environment control many spectral features, including the vibronic and inhomogeneous broadening present in spectral line shapes. For the cresyl violet chromophore in methanol, we here analyze and isolate the effect of specific chromophore-solvent interactions on simulated spectral densities, reorganization energies, and linear absorption spectra. Employing both force field and ab initio molecular dynamics trajectories along with the inclusion of only certain solvent molecules in the excited-state calculations, we determine that the methanol molecules axial to the chromophore are responsible for the majority of inhomogeneous broadening, with a single methanol molecule that forms an axial hydrogen bond dominating the response. The strong peripheral hydrogen bonds do not contribute to spectral broadening, as they are very stable throughout the dynamics and do not lead to increased energy-gap fluctuations. We also find that treating the strong peripheral hydrogen bonds as molecular mechanical point charges during the molecular dynamics simulation underestimates the vibronic coupling. Including these peripheral hydrogen bonding methanol molecules in the quantum-mechanical region in a geometry optimization increases the vibronic coupling, suggesting that a more advanced treatment of these strongly interacting solvent molecules during the molecular dynamics trajectory may be necessary to capture the full vibronic spectral broadening.
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Affiliation(s)
- Christopher A Myers
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Shao-Yu Lu
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Sapana Shedge
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Arthur Pyuskulyan
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Katherine Donahoe
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Ajay Khanna
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Liang Shi
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Christine M Isborn
- Department of Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
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2
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Dellai A, Naim C, Cerezo J, Prampolini G, Castet F. Dynamic effects on the nonlinear optical properties of donor acceptor stenhouse adducts: insights from combined MD + QM simulations. Phys Chem Chem Phys 2024; 26:13639-13654. [PMID: 38511505 DOI: 10.1039/d4cp00310a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
The second-order nonlinear optical (NLO) responses of a donor-acceptor stenhouse adduct (DASA) are investigated by using a computational approach combining molecular dynamics simulations and density functional theory (DFT) calculations. Specific force fields for the open and closed photoswitching forms are first parameterized and validated according to the Joyce protocol, in order to finely reproduce the geometrical features and potential energy surfaces of both isomers in chloroform solution. Then, DFT calculations are performed on structural snapshots extracted at regular time steps of the MD trajectories to address the influence of the thermalized conformational dynamics on the NLO responses related to hyper-Rayleigh scattering (HRS) experiments. We show that accounting for the structural dynamics largely enhances the HRS hyperpolarizability (βHRS) compared to DFT calculations considering solely equilibrium geometries, and greatly improves the agreement with experimental measurements. Furthermore, we show that the NLO responses of the NLO-active open form are correlated with the bond order alternation along the triene bridge connecting the donor and acceptor moieties, which is rationalized using simple essential state models.
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Affiliation(s)
- Angela Dellai
- Univ. Bordeaux, CNRS, Bordeaux INP, Institut des Sciences Moléculaires, UMR 5255, F-33400 Talence, France.
| | - Carmelo Naim
- Univ. Bordeaux, CNRS, Bordeaux INP, Institut des Sciences Moléculaires, UMR 5255, F-33400 Talence, France.
- Donostia International Physics Center (DIPC), Manuel Lardizabal Ibilbidea 4, 20018 Donostia, Euskadi, Spain
| | - Javier Cerezo
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | | | - Frédéric Castet
- Univ. Bordeaux, CNRS, Bordeaux INP, Institut des Sciences Moléculaires, UMR 5255, F-33400 Talence, France.
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3
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Cerezo J, Gao S, Armaroli N, Ingrosso F, Prampolini G, Santoro F, Ventura B, Pastore M. Non-Phenomenological Description of the Time-Resolved Emission in Solution with Quantum-Classical Vibronic Approaches-Application to Coumarin C153 in Methanol. Molecules 2023; 28:molecules28093910. [PMID: 37175320 PMCID: PMC10180259 DOI: 10.3390/molecules28093910] [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: 03/09/2023] [Revised: 04/27/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
We report a joint experimental and theoretical work on the steady-state spectroscopy and time-resolved emission of the coumarin C153 dye in methanol. The lowest energy excited state of this molecule is characterized by an intramolecular charge transfer thus leading to remarkable shifts of the time-resolved emission spectra, dictated by the methanol reorganization dynamics. We selected this system as a prototypical test case for the first application of a novel computational protocol aimed at the prediction of transient emission spectral shapes, including both vibronic and solvent effects, without applying any phenomenological broadening. It combines a recently developed quantum-classical approach, the adiabatic molecular dynamics generalized vertical Hessian method (Ad-MD|gVH), with nonequilibrium molecular dynamics simulations. For the steady-state spectra we show that the Ad-MD|gVH approach is able to reproduce quite accurately the spectral shapes and the Stokes shift, while a ∼0.15 eV error is found on the prediction of the solvent shift going from gas phase to methanol. The spectral shape of the time-resolved emission signals is, overall, well reproduced, although the simulated spectra are slightly too broad and asymmetric at low energies with respect to experiments. As far as the spectral shift is concerned, the calculated spectra from 4 ps to 100 ps are in excellent agreement with experiments, correctly predicting the end of the solvent reorganization after about 20 ps. On the other hand, before 4 ps solvent dynamics is predicted to be too fast in the simulations and, in the sub-ps timescale, the uncertainty due to the experimental time resolution (300 fs) makes the comparison less straightforward. Finally, analysis of the reorganization of the first solvation shell surrounding the excited solute, based on atomic radial distribution functions and orientational correlations, indicates a fast solvent response (≈100 fs) characterized by the strengthening of the carbonyl-methanol hydrogen bond interactions, followed by the solvent reorientation, occurring on the ps timescale, to maximize local dipolar interactions.
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Affiliation(s)
- Javier Cerezo
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Institute of Chemistry of OrganoMetallic Compounds (ICCOM), National Research Council of Italy (CNR), Area di Ricerca di Pisa, Via Moruzzi 1, I-56124 Pisa, Italy
| | - Sheng Gao
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy
| | - Nicola Armaroli
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy
| | - Francesca Ingrosso
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), F-54000 Nancy, France
| | - Giacomo Prampolini
- Institute of Chemistry of OrganoMetallic Compounds (ICCOM), National Research Council of Italy (CNR), Area di Ricerca di Pisa, Via Moruzzi 1, I-56124 Pisa, Italy
| | - Fabrizio Santoro
- Institute of Chemistry of OrganoMetallic Compounds (ICCOM), National Research Council of Italy (CNR), Area di Ricerca di Pisa, Via Moruzzi 1, I-56124 Pisa, Italy
| | - Barbara Ventura
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), Via P. Gobetti 101, I-40129 Bologna, Italy
| | - Mariachiara Pastore
- Université de Lorraine & CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT), F-54000 Nancy, France
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4
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Cerezo J, García-Iriepa C, Santoro F, Navizet I, Prampolini G. Unraveling the contributions to the spectral shape of flexible dyes in solution: insights on the absorption spectrum of an oxyluciferin analogue. Phys Chem Chem Phys 2023; 25:5007-5020. [PMID: 36722876 DOI: 10.1039/d2cp05701h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We present a computational investigation of the absorption spectrum in water of 5,5-spirocyclopropyl-oxyluciferin (5,5-CprOxyLH), an analogue of the emitter compound responsible for the bioluminescence in fireflies. Several factors participate in determining the 5,5-CprOxyLH's spectral shape: (i) the contribution of the four close-energy excited states, which show significant non-adiabatic couplings, (ii) the flexible molecular structure and (iii) the specific interactions established with the surrounding environment, which strongly couple the protic solvent dynamics with the dye's spectral response. To tackle the challenge to capture and dissect the role of all these effects we preliminarily investigate the role of non-adiabatic couplings with quantum dynamics simulations and a linear vibronic coupling model in the gas phase. Then, we account for both the molecular flexibility and solvent interactions by resorting to a mixed quantum classical protocol, named Adiabatic Molecular Dynamics generalized Vertical Gradient (Ad-MD|gVG), which is built on a method recently proposed by some of us. It is rooted in the partition between stiff degrees of freedom of the dye, accounted for at the vibronic level within the harmonic approximation, and flexible degrees of freedom of the solute (and of the solvent), described classically through a sampling based on Molecular Dynamics (MD). Ad-MD|gVG avoids spurious effects arising in the excited state Hessians due to non-adiabatic couplings, and can therefore be applied to account for the contributions of the first four excited states to the 5,5-CprOxyLH absorption spectrum. The final simulated spectrum is in very good agreement with the experiment, especially when the MD is driven by a refined quantum-mechanically derived force-field. More importantly, the origin of each separate contribution to the spectral shape is appropriately accounted for, paving the way to future applications of the method to more complex systems or alternative spectroscopies, as emission or circular dichroism.
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Affiliation(s)
- Javier Cerezo
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain. .,CNR - Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
| | - Cristina García-Iriepa
- Universidad de Alcalá, Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), 28806 Alcalá de Henares (Madrid), Spain. .,Universidad de Alcalá, Instituto de Investigación Química "Andrés M. del Río" (IQAR), 28806 Alcalá de Henares (Madrid), Spain
| | - Fabrizio Santoro
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
| | - Isabelle Navizet
- Univ Gustave Eiffel, Univ Paris Est Creteil, CNRS, UMR 8208, MSME, F-77454 Marne-la-Vallée, France
| | - Giacomo Prampolini
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
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5
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Prampolini G, Campetella M, Ferretti A. Solvent effects on catechol's binding affinity: investigating the role of the intra-molecular hydrogen bond through a multi-level computational approach. Phys Chem Chem Phys 2023; 25:2523-2536. [PMID: 36602108 DOI: 10.1039/d2cp04500a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The subtle interplay between the inter-molecular interactions established by catechol with the surrounding solvent and the intra-molecular hydrogen bond (HB) characterizing its conformational dynamics is investigated through a multi-level computational approach. First, quantum mechanical (QM) calculations are employed to accurately characterize both large portions of the catechol's potential energy surface and the interaction energy with neighboring solvent molecules. The acquired information is thereafter exploited to develop a QM derived force-field (QMD-FF), in turn employed in molecular dynamics (MD) simulations based on classical mechanics. The reliability of the QMD-FF is further validated through a comparison with the outcomes of ab initio molecular dynamics, also purposely carried out in this work. In agreement with recent experimental findings, the MD results reveal remarkable differences in the conformational behavior of isolated and solvated catechol, as well as among the investigated solvents, namely water, acetonitrile or cyclohexane. The rather strong intramolecular HB, settled between the vicinal phenolic groups and maintained in the gas phase, loses stability when catechol is solvated in polar solvents, and is definitively lost in protic solvents such as water. In fact, the internal energy increase associated with the rotation of one hydroxyl group and the breaking of the internal HB is well compensated by the intermolecular HB network available when both phenolic hydrogens point toward the surrounding solvent. In such a case, catechol is stabilized in a chelating conformation, which in turn could be very effective in water removal and surface anchoring. Besides unraveling the role of the different contributors that govern catechol's conformational dynamics, the QMD-FF developed in this work could be in future employed to model larger catechol containing molecules, due to its accuracy to reliably model both internal flexibility and solvent effects, while exploiting MD computational benefits to include more complex players as for instance surfaces, ions or biomolecules.
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Affiliation(s)
- Giacomo Prampolini
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
| | - Marco Campetella
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via Aldo Moro 2 SI, Siena, I-53100, Italy
| | - Alessandro Ferretti
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
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6
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Greff da Silveira L, Livotto PR, Padula D, Vilhena JG, Prampolini G. Accurate Quantum-Mechanically Derived Force-Fields through a Fragment-Based Approach: Balancing Specificity and Transferability in the Prediction of Self-Assembly in Soft Matter. J Chem Theory Comput 2022; 18:6905-6919. [PMID: 36260420 DOI: 10.1021/acs.jctc.2c00747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The wide range of time/length scales covered by self-assembly in soft matter makes molecular dynamics (MD) the ideal candidate for simulating such a supramolecular phenomenon at an atomistic level. However, the reliability of MD outcomes heavily relies on the accuracy of the adopted force-field (FF). The spontaneous re-ordering in liquid crystalline materials stands as a clear example of such collective self-assembling processes, driven by a subtle and delicate balance between supramolecular interactions and single-molecule flexibility. General-purpose transferable FFs often dramatically fail to reproduce such complex phenomena, for example, the error on the transition temperatures being larger than 100 K. Conversely, quantum-mechanically derived force-fields (QMD-FFs), specifically tailored for the target system, were recently shown (J. Phys. Chem. Lett.2022,13, 243) to allow for the required accuracy as they not only well reproduced transition temperatures but also yielded a quantitative agreement with the experiment on a wealth of structural, dynamic, and thermodynamic properties. The main drawback of this strategy stands in the computational burden connected to the numerous quantum mechanical (QM) calculations usually required for a target-specific parameterization, which has undoubtedly hampered the routine application of QMD-FFs. In this work, we propose a fragment-based strategy to extend the applicability of QMD-FFs, in which the amount of QM calculations is significantly reduced, being a single-molecule-optimized geometry and its Hessian matrix the only QM information required. To validate this route, a new FF is assembled for a large mesogen, exploiting the parameters obtained for two smaller liquid crystalline molecules, in this and previous work. Lengthy MD simulations are carried out with the new transferred QMD-FF, observing again a spontaneous re-orientation in the correct range of temperatures, with good agreement with the available experimental measures. The present results strongly suggest that a partial transfer of QMD-FF parameters can be invoked without a significant loss of accuracy, thus paving the way to exploit the method's intrinsic predictive capabilities in the simulation of novel soft materials.
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Affiliation(s)
- Leandro Greff da Silveira
- Instituto de Química (Universidade Federal do Rio Grande do Sul), Avenida Bento Gonçalves 9500, CEP 91501-970Porto Alegre, Brazil
| | - Paolo Roberto Livotto
- Instituto de Química (Universidade Federal do Rio Grande do Sul), Avenida Bento Gonçalves 9500, CEP 91501-970Porto Alegre, Brazil
| | - Daniele Padula
- Dipartimento di Biotecnologie, Chimica e Farmacia (Università di Siena), via Aldo Moro 2, 53100Siena, SI, Italy
| | - J G Vilhena
- Departamento de Física Teórica de la Materia Condensada (Universidad Autónoma de Madrid), E-28049Madrid, Spain.,Condensed Matter Physics Center (IFIMAC) (Universidad Autónoma de Madrid), E-28049Madrid, Spain
| | - Giacomo Prampolini
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124Pisa, Italy
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7
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Green JA, Jouybari MY, Aranda D, Improta R, Santoro F. Nonadiabatic Absorption Spectra and Ultrafast Dynamics of DNA and RNA Photoexcited Nucleobases. Molecules 2021; 26:1743. [PMID: 33804640 PMCID: PMC8003674 DOI: 10.3390/molecules26061743] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/12/2021] [Accepted: 03/14/2021] [Indexed: 11/16/2022] Open
Abstract
We have recently proposed a protocol for Quantum Dynamics (QD) calculations, which is based on a parameterisation of Linear Vibronic Coupling (LVC) Hamiltonians with Time Dependent (TD) Density Functional Theory (TD-DFT), and exploits the latest developments in multiconfigurational TD-Hartree methods for an effective wave packet propagation. In this contribution we explore the potentialities of this approach to compute nonadiabatic vibronic spectra and ultrafast dynamics, by applying it to the five nucleobases present in DNA and RNA. For all of them we computed the absorption spectra and the dynamics of ultrafast internal conversion (100 fs timescale), fully coupling the first 2-3 bright states and all the close by dark states, for a total of 6-9 states, and including all the normal coordinates. We adopted two different functionals, CAM-B3LYP and PBE0, and tested the effect of the basis set. Computed spectra are in good agreement with the available experimental data, remarkably improving over pure electronic computations, but also with respect to vibronic spectra obtained neglecting inter-state couplings. Our QD simulations indicate an effective population transfer from the lowest energy bright excited states to the close-lying dark excited states for uracil, thymine and adenine. Dynamics from higher-energy states show an ultrafast depopulation toward the more stable ones. The proposed protocol is sufficiently general and automatic to promise to become useful for widespread applications.
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Affiliation(s)
- James A. Green
- CNR—Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini (IBB-CNR), Via Mezzocannone 16, I-80136 Napoli, Italy;
| | - Martha Yaghoubi Jouybari
- CNR—Consiglio Nazionale Delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area Della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy; (M.Y.J.); (D.A.)
| | - Daniel Aranda
- CNR—Consiglio Nazionale Delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area Della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy; (M.Y.J.); (D.A.)
| | - Roberto Improta
- CNR—Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini (IBB-CNR), Via Mezzocannone 16, I-80136 Napoli, Italy;
| | - Fabrizio Santoro
- CNR—Consiglio Nazionale Delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area Della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy; (M.Y.J.); (D.A.)
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8
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Segalina A, Cerezo J, Prampolini G, Santoro F, Pastore M. Accounting for Vibronic Features through a Mixed Quantum-Classical Scheme: Structure, Dynamics, and Absorption Spectra of a Perylene Diimide Dye in Solution. J Chem Theory Comput 2020; 16:7061-7077. [DOI: 10.1021/acs.jctc.0c00919] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Alekos Segalina
- Université de Lorraine & CNRS, LPCT, UMR 7019, F-54000 Nancy, France
| | - Javier Cerezo
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Giacomo Prampolini
- Istituto di Chimica dei Composti Organo Metallici, Consiglio Nazionale delle Ricerche, (ICCOM-CNR) SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Fabrizio Santoro
- Istituto di Chimica dei Composti Organo Metallici, Consiglio Nazionale delle Ricerche, (ICCOM-CNR) SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
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9
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Diez-Cabanes V, Prampolini G, Francés-Monerris A, Monari A, Pastore M. Iron's Wake: The Performance of Quantum Mechanical-Derived Versus General-Purpose Force Fields Tested on a Luminescent Iron Complex. Molecules 2020; 25:molecules25133084. [PMID: 32640764 PMCID: PMC7411876 DOI: 10.3390/molecules25133084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 12/29/2022] Open
Abstract
Recently synthetized iron complexes have achieved long-lived excited states and stabilities which are comparable, or even superior, to their ruthenium analogues, thus representing an eco-friendly and cheaper alternative to those materials based on rare metals. Most of computational tools which could help unravel the origin of this large efficiency rely on ab-initio methods which are not able, however, to capture the nanosecond time scale underlying these photophysical processes and the influence of their realistic environment. Therefore, it exists an urgent need of developing new low-cost, but still accurate enough, computational methodologies capable to deal with the steady-state and transient spectroscopy of transition metal complexes in solution. Following this idea, here we focus on the comparison between general-purpose transferable force-fields (FFs), directly available from existing databases, and specific quantum mechanical derived FFs (QMD-FFs), obtained in this work through the Joyce procedure. We have chosen a recently reported FeIII complex with nanosecond excited-state lifetime as a representative case. Our molecular dynamics (MD) simulations demonstrated that the QMD-FF nicely reproduces the structure and the dynamics of the complex and its chemical environment within the same precision as higher cost QM methods, whereas general-purpose FFs failed in this purpose. Although in this particular case the chemical environment plays a minor role on the photo physics of this system, these results highlight the potential of QMD-FFs to rationalize photophysical phenomena provided an accurate QM method to derive its parameters is chosen.
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Affiliation(s)
- Valentin Diez-Cabanes
- Université de Lorraine & CNRS, LPCT UMR 7019, F-54000 Nancy, France;
- Correspondence: (V.D.-C.); (G.P.); (A.M.); (M.P.)
| | - Giacomo Prampolini
- Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
- Correspondence: (V.D.-C.); (G.P.); (A.M.); (M.P.)
| | - Antonio Francés-Monerris
- Université de Lorraine & CNRS, LPCT UMR 7019, F-54000 Nancy, France;
- Departament de Química Física, Universitat de València, 46100 Burjassot, Spain
| | - Antonio Monari
- Université de Lorraine & CNRS, LPCT UMR 7019, F-54000 Nancy, France;
- Correspondence: (V.D.-C.); (G.P.); (A.M.); (M.P.)
| | - Mariachiara Pastore
- Université de Lorraine & CNRS, LPCT UMR 7019, F-54000 Nancy, France;
- Correspondence: (V.D.-C.); (G.P.); (A.M.); (M.P.)
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10
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Cerezo J, Aranda D, Avila Ferrer FJ, Prampolini G, Santoro F. Adiabatic-Molecular Dynamics Generalized Vertical Hessian Approach: A Mixed Quantum Classical Method To Compute Electronic Spectra of Flexible Molecules in the Condensed Phase. J Chem Theory Comput 2020; 16:1215-1231. [PMID: 31855424 DOI: 10.1021/acs.jctc.9b01009] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We present a general mixed quantum classical method that couples classical molecular dynamics (MD) and vibronic models to compute the shape of electronic spectra of flexible molecules in the condensed phase without, in principle, any phenomenological broadening. It is based on a partition of the nuclear motions of the solute + solvent system in "soft" and "stiff" vibrational modes and an adiabatic hypothesis that assumes that stiff modes are much faster than soft ones. In this framework, the spectrum is rigorously expressed as a conformational integral of quantum vibronic spectra along the stiff coordinates only. Soft modes enter at the classical level through the conformational distribution that is sampled with classical MD runs. In each configuration, reduced-dimensionality quadratic Hamiltonians are built in the space of the stiff coordinates only, thanks to a generalization of the Vertical Hessian harmonic model and an iterative application of projectors in internal coordinates to remove soft modes. Quantum vibronic spectra, specific for each sampled configuration of the soft coordinates, are then computed at the desired temperature with efficient time-dependent techniques, and the global spectrum simply arises from their average. For consistency of the whole procedure, classical MD runs are performed with quantum-mechanically derived force fields, parameterized at the same level of theory selected for generating the quadratic Hamiltonians along the stiff coordinates. Application to N-methyl-6-oxyquinolinium betaine in water, dithiophene in ethanol, and cyanidine in water is presented to show the performance of the method.
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Affiliation(s)
| | - Daniel Aranda
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa , Area della Ricerca, via G. Moruzzi 1 , I-56124 Pisa , Italy.,Departamento de Química Física, Facultad de Ciencias, Andalucía Tech , Universidad de Málaga , E-29071 Málaga , Spain
| | - Francisco José Avila Ferrer
- Departamento de Química Física, Facultad de Ciencias, Andalucía Tech , Universidad de Málaga , E-29071 Málaga , Spain
| | - Giacomo Prampolini
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa , Area della Ricerca, via G. Moruzzi 1 , I-56124 Pisa , Italy
| | - Fabrizio Santoro
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa , Area della Ricerca, via G. Moruzzi 1 , I-56124 Pisa , Italy
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11
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Prampolini G, Ingrosso F, Segalina A, Caramori S, Foggi P, Pastore M. Dynamical and Environmental Effects on the Optical Properties of an Heteroleptic Ru(II)–Polypyridine Complex: A Multilevel Approach Combining Accurate Ground and Excited State QM-Derived Force Fields, MD and TD-DFT. J Chem Theory Comput 2018; 15:529-545. [DOI: 10.1021/acs.jctc.8b01031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Giacomo Prampolini
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Francesca Ingrosso
- Université de Lorraine, CNRS, Laboratoire de Physique et Chimie Théoriques, F-54000 Nancy, France
| | - Alekos Segalina
- Université de Lorraine, CNRS, Laboratoire de Physique et Chimie Théoriques, F-54000 Nancy, France
| | - Stefano Caramori
- Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara, Via Luigi Borsari 46, I-44100, Ferrara, Italy
| | - Paolo Foggi
- European Laboratory for Non Linear Spectroscopy (LENS), Università di Firenze, Via Nello Carrara 1, I-50019 Sesto Fiorentino Florence, Italy
- INO−CNR, Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo Fermi 6, I-50125 Florence, Italy
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy
| | - Mariachiara Pastore
- Université de Lorraine, CNRS, Laboratoire de Physique et Chimie Théoriques, F-54000 Nancy, France
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12
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Greff da Silveira L, Jacobs M, Prampolini G, Livotto PR, Cacelli I. Development and Validation of Quantum Mechanically Derived Force-Fields: Thermodynamic, Structural, and Vibrational Properties of Aromatic Heterocycles. J Chem Theory Comput 2018; 14:4884-4900. [PMID: 30040902 DOI: 10.1021/acs.jctc.8b00218] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A selection of several aromatic molecules, representative of the important class of heterocyclic compounds, has been considered for testing and validating an automated Force Field (FF) parametrization protocol, based only on Quantum Mechanical data. The parametrization is carried out separately for the intra- and intermolecular contributions, employing respectively the Joyce and Picky software packages, previously implemented and refined in our research group. The whole approach is here automated and integrated with a computationally effective yet accurate method, devised very recently ( J. Chem. THEORY Comput., 2018, 14, 543-556) to evaluate a large number of dimer interaction energies. The resulting quantum mechanically derived FFs are then used in extensive molecular dynamics simulations, in order to evaluate a number of thermodynamic, structural, and dynamic properties of the heterocycle's gas and liquid phases. The comparison with the available experimental data is good and furnishes a validation of the presented approach, which can be confidently exploited for the design of novel and more complex materials.
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Affiliation(s)
- Leandro Greff da Silveira
- Instituto de Química , Universidade Federal do Rio Grande do Sul , Avenida Bento Gonçalves 9500 , CEP 91501-970 Porto , Alegre , Brazil
| | - Matheus Jacobs
- Instituto de Química , Universidade Federal do Rio Grande do Sul , Avenida Bento Gonçalves 9500 , CEP 91501-970 Porto , Alegre , Brazil.,Institut für Physik , Humboldt-Universität zu Berlin , Newtonstrasse 15 , 12489 , Berlin , Germany.,IRIS Adelrshof , Humboldt-Universität zu Berlin , Zum Großen Windkanal 6 , 12489 , Berlin , Germany
| | - Giacomo Prampolini
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1 , I-56124 Pisa , Italy
| | - Paolo Roberto Livotto
- Instituto de Química , Universidade Federal do Rio Grande do Sul , Avenida Bento Gonçalves 9500 , CEP 91501-970 Porto , Alegre , Brazil
| | - Ivo Cacelli
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1 , I-56124 Pisa , Italy.,Dipartimento di Chimica e Chimica Industriale , Università di Pisa , Via G. Moruzzi 13 , I-56124 Pisa , Italy
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13
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Kjellgren ER, Haugaard Olsen JM, Kongsted J. Importance of Accurate Structures for Quantum Chemistry Embedding Methods: Which Strategy Is Better? J Chem Theory Comput 2018; 14:4309-4319. [DOI: 10.1021/acs.jctc.8b00202] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Erik Rosendahl Kjellgren
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jógvan Magnus Haugaard Olsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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14
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Cerezo J, Prampolini G, Cacelli I. Developing accurate intramolecular force fields for conjugated systems through explicit coupling terms. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2254-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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15
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Cerezo J, Aranda D, Avila Ferrer FJ, Prampolini G, Mazzeo G, Longhi G, Abbate S, Santoro F. Toward a general mixed quantum/classical method for the calculation of the vibronic ECD of a flexible dye molecule with different stable conformers: Revisiting the case of 2,2,2-trifluoro-anthrylethanol. Chirality 2018; 30:730-743. [DOI: 10.1002/chir.22853] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/19/2018] [Accepted: 02/20/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Javier Cerezo
- Departamento de Química Física; Universidad de Murcia; Murcia Spain
| | - Daniel Aranda
- Consiglio Nazionale delle Ricerche-Istituto di Chimica dei Composti Organometallici (ICCOM-CNR); Pisa Italy
- Departamento de Química Física; Universidad de Málaga; Málaga Spain
| | | | - Giacomo Prampolini
- Consiglio Nazionale delle Ricerche-Istituto di Chimica dei Composti Organometallici (ICCOM-CNR); Pisa Italy
| | - Giuseppe Mazzeo
- Dipartimento di Medicina Molecolare e Traslazionale; Università di Brescia; Brescia Italy
| | - Giovanna Longhi
- Dipartimento di Medicina Molecolare e Traslazionale; Università di Brescia; Brescia Italy
| | - Sergio Abbate
- Dipartimento di Medicina Molecolare e Traslazionale; Università di Brescia; Brescia Italy
| | - Fabrizio Santoro
- Consiglio Nazionale delle Ricerche-Istituto di Chimica dei Composti Organometallici (ICCOM-CNR); Pisa Italy
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16
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Morzan UN, Alonso de Armiño DJ, Foglia NO, Ramírez F, González Lebrero MC, Scherlis DA, Estrin DA. Spectroscopy in Complex Environments from QM–MM Simulations. Chem Rev 2018; 118:4071-4113. [DOI: 10.1021/acs.chemrev.8b00026] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Uriel N. Morzan
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
| | - Diego J. Alonso de Armiño
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
| | - Nicolás O. Foglia
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
| | - Francisco Ramírez
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
| | - Mariano C. González Lebrero
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
| | - Damián A. Scherlis
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
| | - Darío A. Estrin
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, C1428EHA Buenos Aires, Argentina
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17
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Andreussi O, Prandi IG, Campetella M, Prampolini G, Mennucci B. Classical Force Fields Tailored for QM Applications: Is It Really a Feasible Strategy? J Chem Theory Comput 2017; 13:4636-4648. [DOI: 10.1021/acs.jctc.7b00777] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Oliviero Andreussi
- Institute
of Computational Science, Università della Svizzera Italiana, Via Giuseppe Buffi 13, CH-6904 Lugano, Switzerland
- Theory
and Simulations of Materials (THEOS) and National Centre for Computational
Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Station 12, CH-1015 Lausanne, Switzerland
| | - Ingrid G. Prandi
- Department
of Chemistry, University of Pisa, Via Giuseppe Moruzzi 3, I-56124 Pisa, Italy
| | - Marco Campetella
- Department
of Chemistry, University of Pisa, Via Giuseppe Moruzzi 3, I-56124 Pisa, Italy
| | - Giacomo Prampolini
- CNR,
UOS Pisa, Istituto di Chimica dei Composti OrganoMetallici ICCOM CNR, Area della Ricerca, Via Giuseppe Moruzzi 1, I-56124 Pisa, Italy
| | - Benedetta Mennucci
- Department
of Chemistry, University of Pisa, Via Giuseppe Moruzzi 3, I-56124 Pisa, Italy
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18
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Padula D, Cerezo J, Pescitelli G, Santoro F. The shape of the electronic circular dichroism spectrum of (2,6-dimethylphenyl)(phenyl)methanol: interplay between conformational equilibria and vibronic effects. Phys Chem Chem Phys 2017; 19:32349-32360. [DOI: 10.1039/c7cp06369e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Analysis of the interplay between conformational equilibria, solvent effects and vibronic contributions in the ECD spectra.
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Affiliation(s)
- Daniele Padula
- Department of Chemistry
- University of Liverpool
- Liverpool L69 7ZD
- UK
| | - Javier Cerezo
- Departamento de Química Física
- Universidad de Murcia
- 30100 Murcia
- Spain
| | - Gennaro Pescitelli
- Università di Pisa
- Dipartimento di Chimica e Chimica Industriale
- I-56124 Pisa
- Italy
| | - Fabrizio Santoro
- Consiglio Nazionale delle Ricerche – CNR
- Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR)
- Pisa
- Italy
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19
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Cerezo J, Mazzeo G, Longhi G, Abbate S, Santoro F. Quantum-Classical Calculation of Vibronic Spectra along a Reaction Path: The Case of the ECD of Easily Interconvertible Conformers with Opposite Chiral Responses. J Phys Chem Lett 2016; 7:4891-4897. [PMID: 27934048 DOI: 10.1021/acs.jpclett.6b02484] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a novel mixed method suitable for computing the low-to-middle resolution spectra of systems characterized by a large-amplitude motion s (defined by either a reaction or an internal path) coupled to a bath of harmonic oscillators r, which change with s. The method is based on an adiabatic approximation whereby s is considered much slower than r degrees of freedom and is treated classically. We show that the spectrum can be obtained by a suitable average of quantum vibronic spectra of the fast coordinates computed at representative values of the slow coordinate along the path. By our method we calculate the electronic circular dichroism (ECD) of 2,2,2-trifluoro-anthryl-ethanol, which possesses two conformers with opposite chirality separated by a low-energy barrier. Path-averaged spectra are significantly different from those obtained only at the stable minima: Agreement with experiment is improved. The method represents a generalization of those currently based on harmonic approximation.
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Affiliation(s)
- Javier Cerezo
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Giuseppe Mazzeo
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia , Viale Europa 11, I-25123 Brescia, Italy
| | - Giovanna Longhi
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia , Viale Europa 11, I-25123 Brescia, Italy
| | - Sergio Abbate
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia , Viale Europa 11, I-25123 Brescia, Italy
| | - Fabrizio Santoro
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
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20
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Prampolini G, Campetella M, De Mitri N, Livotto PR, Cacelli I. Systematic and Automated Development of Quantum Mechanically Derived Force Fields: The Challenging Case of Halogenated Hydrocarbons. J Chem Theory Comput 2016; 12:5525-5540. [DOI: 10.1021/acs.jctc.6b00705] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Giacomo Prampolini
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Marco Campetella
- Dipartimento
di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi
13, I-56124 Pisa, Italy
| | - Nicola De Mitri
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Paolo Roberto Livotto
- Instituto
de Química, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9500, CEP 91501-970 Porto Alegre, Brazil
| | - Ivo Cacelli
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi
13, I-56124 Pisa, Italy
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21
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Cerezo J, Santoro F. Revisiting Vertical Models To Simulate the Line Shape of Electronic Spectra Adopting Cartesian and Internal Coordinates. J Chem Theory Comput 2016; 12:4970-4985. [PMID: 27586086 DOI: 10.1021/acs.jctc.6b00442] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Vertical models for the simulation of spectroscopic line shapes expand the potential energy surface (PES) of the final state around the equilibrium geometry of the initial state. These models provide, in principle, a better approximation of the region of the band maximum. At variance, adiabatic models expand each PES around its own minimum. In the harmonic approximation, when the minimum energy structures of the two electronic states are connected by large structural displacements, adiabatic models can breakdown and are outperformed by vertical models. However, the practical application of vertical models faces the issues related to the necessity to perform a frequency analysis at a nonstationary point. In this contribution we revisit vertical models in harmonic approximation adopting both Cartesian (x) and valence internal curvilinear coordinates (s). We show that when x coordinates are used, the vibrational analysis at nonstationary points leads to a deficient description of low-frequency modes, for which spurious imaginary frequencies may even appear. This issue is solved when s coordinates are adopted. It is however necessary to account for the second derivative of s with respect to x, which here we compute analytically. We compare the performance of the vertical model in the s-frame with respect to adiabatic models and previously proposed vertical models in x- or Q1-frame, where Q1 are the normal coordinates of the initial state computed as combination of Cartesian coordinates. We show that for rigid molecules the vertical approach in the s-frame provides a description of the final state very close to the adiabatic picture. For sizable displacements it is a solid alternative to adiabatic models, and it is not affected by the issues of vertical models in x- and Q1-frames, which mainly arise when temperature effects are included. In principle the G matrix depends on s, and this creates nonorthogonality problems of the Duschinsky matrix connecting the normal modes of initial and final states in adiabatic approaches. We highlight that such a dependence of G on s is also an issue in vertical models, due to the necessity to approximate the kinetic term in the Hamiltonian when setting up the so-called GF problem. When large structural differences exist between the initial and the final-state minima, the changes in the G matrix can become too large to be disregarded.
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Affiliation(s)
- Javier Cerezo
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Richerche (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Fabrizio Santoro
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Richerche (ICCOM-CNR) , Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
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22
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Bednarska J, Zaleśny R, Arul Murugan N, Bartkowiak W, Ågren H, Odelius M. Elucidating the Mechanism of Zn(2+) Sensing by a Bipyridine Probe Based on Two-Photon Absorption. J Phys Chem B 2016; 120:9067-75. [PMID: 27494451 DOI: 10.1021/acs.jpcb.6b04949] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, we examine, by means of computational methods, the mechanism of Zn(2+) sensing by a bipyridine-centered, D-π-A-π-D-type ratiometric molecular probe. According to recently published experimental data [Divya, K. P.; Sreejith, S.; Ashokkumar, P.; Yuzhan, K.; Peng, Q.; Maji, S. K.; Tong, Y.; Yu, H.; Zhao, Y.; Ramamurthy, P.; Ajayaghosh, A. A ratiometric fluorescent molecular probe with enhanced two-photon response upon Zn(2+) binding for in vitro and in vivo bioimaging. Chem. Sci. 2014, 5, 3469-3474], after coordination to zinc ions the probe exhibits a large enhancement of the two-photon absorption cross section. The goal of our investigation was to elucidate the mechanism behind this phenomenon. For this purpose, linear and nonlinear optical properties of the unbound (cation-free) and bound probe were calculated, including the influence of solute-solvent interactions, implicitly using a polarizable continuum model and explicitely employing the QM/MM approach. Because the results of the calculations indicate that many conformers of the probe are energetically accessible at room temperature in solution and hence contribute to the signal, structure-property relationships were also taken into account. Results of our simulations demonstrate that the one-photon absorption bands for both the unbound and bound forms correspond to the bright π → π* transition to the first excited state, which, on the other hand, exhibits negligible two-photon activity. On the basis of the results of the quadratic response calculations, we put forward a notion that it is the second excited state that gives the strong signal in the experimental nonlinear spectrum. To explain the differences in the two-photon absorption activity for the two lowest-lying excited states and nonlinear response enhancement upon binding, we employed the generalized few-state model including the ground, first, and second excited states. The analysis of the optical channel suggests that the large two-photon response is due to the coordination-induced increase of the transition moment from the first to the second excited state.
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Affiliation(s)
- Joanna Bednarska
- Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology , Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - Robert Zaleśny
- Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology , Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - N Arul Murugan
- Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology , SE-10691 Stockholm, Sweden
| | - Wojciech Bartkowiak
- Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology , Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - Hans Ågren
- Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology , SE-10691 Stockholm, Sweden
| | - Michael Odelius
- Division of Chemical Physics, Department of Physics, Stockholm University , SE-106 91 Stockholm, Sweden
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