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Kalita P, Medhi B, Singh HK, Bhattacharyya HP, Gupt N, Sarma M. Perturbing π-clouds with Substituents to Study the Effects on Reaction Dynamics of gauche-1,3-Butadiene to Bicyclobutane Electrocyclization. Chemphyschem 2023; 24:e202200727. [PMID: 36281900 DOI: 10.1002/cphc.202200727] [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: 10/01/2022] [Revised: 10/23/2022] [Indexed: 02/03/2023]
Abstract
The conical intersection (CI) governs the ultra-fast relaxation of excited states in a radiationless manner and are observed mainly in photochemical processes. In the current work, we investigated the effects of substituents on the reaction dynamics for the conversion of gauche-1,3-butadiene to bicyclobutane via photochemical electrocyclization. We incorporated both electron withdrawing (-F) and donating (-CH3 ) groups in the conjugated system. In our study, we optimized the minimum energy conical intersection (MECI) geometries using the multi-configurational state-averaged CASSCF approach, whereas, to study the ground state reaction pathways for the substituted derivatives, dispersion corrected, B3LYP-D3 functional was used. The non-adiabatic surface hopping molecular dynamics simulations were performed to observe the behaviour of electronic states involved throughout the photoconversion process. The results obtained from the multi-reference second-order perturbation correction of energy at the XMS-CASPT2 level of theory, topography analysis, and non-adiabatic dynamics suggest that the -CH3 substituted derivatives can undergo faster thermal conversion to the product in the ground state with a smaller activation energy barrier compared to -F substituted derivative. Our study also reveals that the GBUT to BIBUT conversion follows both conrotatory and disrotatory pathways, whereas, on substitution with -F or -CH3 , the conversion proceeds via the conrotatory pathway.
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Affiliation(s)
- Papu Kalita
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, Indian
| | - Biman Medhi
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, Indian
| | - Haobam Kisan Singh
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, Indian
| | | | - Nikhil Gupt
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, Indian.,Current Address: Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, Indian
| | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, Indian
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Zhang D, Liu C. Electronic Structures of Anti-Ferromagnetic Tetraradicals: Ab Initio and Semi-Empirical Studies. J Chem Theory Comput 2016; 12:1714-27. [PMID: 26963572 DOI: 10.1021/acs.jctc.6b00103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The energy relationships and electronic structures of the lowest-lying spin states in several anti-ferromagnetic tetraradical model systems are studied with high-level ab initio and semi-empirical methods. The Full-CI method (FCI), the complete active space second-order perturbation theory (CASPT2), and the n-electron valence state perturbation theory (NEVPT2) are employed to obtain reference results. By comparing the energy relationships predicted from the Heisenberg and Hubbard models with ab initio benchmarks, the accuracy of the widely used Heisenberg model for anti-ferromagnetic spin-coupling in low-spin polyradicals is cautiously tested in this work. It is found that the strength of electron correlation (|U/t|) concerning anti-ferromagnetically coupled radical centers could range widely from strong to moderate correlation regimes and could become another degree of freedom besides the spin multiplicity. Accordingly, the Heisenberg-type model works well in the regime of strong correlation, which reproduces well the energy relationships along with the wave functions of all the spin states. In moderately spin-correlated tetraradicals, the results of the prototype Heisenberg model deviate severely from those of multi-reference electron correlation ab initio methods, while the extended Heisenberg model, containing four-body terms, can introduce reasonable corrections and maintains its accuracy in this condition. In the weak correlation regime, both the prototype Heisenberg model and its extended forms containing higher-order correction terms will encounter difficulties. Meanwhile, the Hubbard model shows balanced accuracy from strong to weak correlation cases and can reproduce qualitatively correct electronic structures, which makes it more suitable for the study of anti-ferromagnetic coupling in polyradical systems.
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Affiliation(s)
- Dawei Zhang
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of the Ministry of Education (MOE), School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, China
| | - Chungen Liu
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of the Ministry of Education (MOE), School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, China
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Schmidt TC, Paasche A, Grebner C, Ansorg K, Becker J, Lee W, Engels B. QM/MM investigations of organic chemistry oriented questions. Top Curr Chem (Cham) 2014; 351:25-101. [PMID: 22392477 DOI: 10.1007/128_2011_309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
About 35 years after its first suggestion, QM/MM became the standard theoretical approach to investigate enzymatic structures and processes. The success is due to the ability of QM/MM to provide an accurate atomistic picture of enzymes and related processes. This picture can even be turned into a movie if nuclei-dynamics is taken into account to describe enzymatic processes. In the field of organic chemistry, QM/MM methods are used to a much lesser extent although almost all relevant processes happen in condensed matter or are influenced by complicated interactions between substrate and catalyst. There is less importance for theoretical organic chemistry since the influence of nonpolar solvents is rather weak and the effect of polar solvents can often be accurately described by continuum approaches. Catalytic processes (homogeneous and heterogeneous) can often be reduced to truncated model systems, which are so small that pure quantum-mechanical approaches can be employed. However, since QM/MM becomes more and more efficient due to the success in software and hardware developments, it is more and more used in theoretical organic chemistry to study effects which result from the molecular nature of the environment. It is shown by many examples discussed in this review that the influence can be tremendous, even for nonpolar reactions. The importance of environmental effects in theoretical spectroscopy was already known. Due to its benefits, QM/MM can be expected to experience ongoing growth for the next decade.In the present chapter we give an overview of QM/MM developments and their importance in theoretical organic chemistry, and review applications which give impressions of the possibilities and the importance of the relevant effects. Since there is already a bunch of excellent reviews dealing with QM/MM, we will discuss fundamental ingredients and developments of QM/MM very briefly with a focus on very recent progress. For the applications we follow a similar strategy.
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Affiliation(s)
- Thomas C Schmidt
- Institut für Phys. und Theor. Chemie, Emil-Fischer-Strasse 42, Campus Hubland Nord, 97074, Würzburg, Germany
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Muñoz-Losa A, Martín ME, Galván IF, Sánchez ML, Aguilar MA. Solvent Effects on the Radiative and Nonradiative Decay of a Model of the Rhodopsin Chromophore. J Chem Theory Comput 2011; 7:4050-9. [DOI: 10.1021/ct200295r] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aurora Muñoz-Losa
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - M. Elena Martín
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - Ignacio Fdez. Galván
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - M. Luz Sánchez
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - Manuel A. Aguilar
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
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Wu W, Su P, Shaik S, Hiberty PC. Classical Valence Bond Approach by Modern Methods. Chem Rev 2011; 111:7557-93. [DOI: 10.1021/cr100228r] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Wei Wu
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Peifeng Su
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Philippe C. Hiberty
- Laboratoire de Chimie Physique, Groupe de Chimie Théorique, CNRS UMR 8000, Université de Paris-Sud, 91405 Orsay Cédex, France
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Hirao H. Correlation diagram approach as a tool for interpreting chemistry: an introductory overview. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Schapiro I, Melaccio F, Laricheva EN, Olivucci M. Using the computer to understand the chemistry of conical intersections. Photochem Photobiol Sci 2011; 10:867-86. [DOI: 10.1039/c0pp00290a] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Trinquier G, Suaud N, Malrieu JP. Theoretical Design of High-Spin Polycyclic Hydrocarbons. Chemistry 2010; 16:8762-72. [DOI: 10.1002/chem.201000044] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tokmachev AM, Boggio-Pasqua M, Mendive-Tapia D, Bearpark MJ, Robb MA. Fluorescence of the perylene radical cation and an inaccessible D0/D1 conical intersection: An MMVB, RASSCF, and TD-DFT computational study. J Chem Phys 2010; 132:044306. [DOI: 10.1063/1.3278545] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Sharir-Ivry A, Shnerb T, Štrajbl M, Shurki A. VB/MM Protein Landscapes: A Study of the SN2 Reaction in Haloalkane Dehalogenase. J Phys Chem B 2010; 114:2212-8. [DOI: 10.1021/jp905143d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Avital Sharir-Ivry
- Department of Medicinal Chemistry and Natural Product, The Institute of Drug Research, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| | - Tamar Shnerb
- Department of Medicinal Chemistry and Natural Product, The Institute of Drug Research, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| | - Marek Štrajbl
- Department of Medicinal Chemistry and Natural Product, The Institute of Drug Research, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| | - Avital Shurki
- Department of Medicinal Chemistry and Natural Product, The Institute of Drug Research, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
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Tokmachev AM, Boggio-Pasqua M, Bearpark MJ, Robb MA. Photostability via Sloped Conical Intersections: A Computational Study of the Pyrene Radical Cation. J Phys Chem A 2008; 112:10881-6. [DOI: 10.1021/jp8044109] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Andrei M. Tokmachev
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom, and Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université Toulouse 3, 118 route de Narbonne, 31062 Toulouse, France
| | - Martial Boggio-Pasqua
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom, and Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université Toulouse 3, 118 route de Narbonne, 31062 Toulouse, France
| | - Michael J. Bearpark
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom, and Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université Toulouse 3, 118 route de Narbonne, 31062 Toulouse, France
| | - Michael A. Robb
- Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom, and Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université Toulouse 3, 118 route de Narbonne, 31062 Toulouse, France
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12
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Tomasello G, Ogliaro F, Bearpark MJ, Robb MA, Garavelli M. Modeling the Photophysics and Photochromic Potential of 1,2-Dihydronaphthalene (DHN): A Combined CASPT2//CASSCF-Topological and MMVB-Dynamical Investigation. J Phys Chem A 2008; 112:10096-107. [DOI: 10.1021/jp802613m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gaia Tomasello
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Equipe de Chimie et Biochimie Théoriques, UMR 7565 - CNRS, Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France, and Department of Chemistry, Imperial College London, London SW7 2AZ U.K
| | - Francois Ogliaro
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Equipe de Chimie et Biochimie Théoriques, UMR 7565 - CNRS, Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France, and Department of Chemistry, Imperial College London, London SW7 2AZ U.K
| | - Michael J. Bearpark
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Equipe de Chimie et Biochimie Théoriques, UMR 7565 - CNRS, Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France, and Department of Chemistry, Imperial College London, London SW7 2AZ U.K
| | - Michael A. Robb
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Equipe de Chimie et Biochimie Théoriques, UMR 7565 - CNRS, Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France, and Department of Chemistry, Imperial College London, London SW7 2AZ U.K
| | - Marco Garavelli
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Equipe de Chimie et Biochimie Théoriques, UMR 7565 - CNRS, Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France, and Department of Chemistry, Imperial College London, London SW7 2AZ U.K
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13
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Sharir-Ivry A, Shurki A. VB/MM—The Validity of the Underlying Approximations. J Phys Chem B 2008; 112:12491-7. [DOI: 10.1021/jp802667y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Avital Sharir-Ivry
- Department of Medicinal Chemistry and Natural Products, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Avital Shurki
- Department of Medicinal Chemistry and Natural Products, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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14
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15
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Sharir-Ivry A, Crown HA, Wu W, Shurki A. Density Embedded VB/MM: A Hybrid ab Initio VB/MM with Electrostatic Embedding. J Phys Chem A 2008; 112:2489-96. [DOI: 10.1021/jp710395b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Avital Sharir-Ivry
- Department of Medicinal Chemistry and Natural Products, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel, and Department of Chemistry, Center for Theoretical Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Hadar A. Crown
- Department of Medicinal Chemistry and Natural Products, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel, and Department of Chemistry, Center for Theoretical Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Wei Wu
- Department of Medicinal Chemistry and Natural Products, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel, and Department of Chemistry, Center for Theoretical Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Avital Shurki
- Department of Medicinal Chemistry and Natural Products, The Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel, and Department of Chemistry, Center for Theoretical Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
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Muñoz Losa A, Fdez. Galván I, Sánchez ML, Martín ME, Aguilar MA. Solvent Effects on Internal Conversions and Intersystem Crossings: The Radiationless De-Excitation of Acrolein in Water. J Phys Chem B 2007; 112:877-84. [DOI: 10.1021/jp075706v] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aurora Muñoz Losa
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - Ignacio Fdez. Galván
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - M. Luz Sánchez
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - M. Elena Martín
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
| | - Manuel A. Aguilar
- Química Física, Universidad de Extremadura, Avda. de Elvas s/n 06071 Badajoz, Spain
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Hall KF, Tokmachev AM, Bearpark MJ, Boggio-Pasqua M, Robb MA. Molecular mechanics-valence bond method for planar conjugated hydrocarbon cations. J Chem Phys 2007; 127:134111. [DOI: 10.1063/1.2770719] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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18
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CASSCF calculations for photoinduced processes in large molecules: Choosing when to use the RASSCF, ONIOM and MMVB approximations. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2007.05.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Muñoz Losa A, Martín ME, Galván IF, Aguilar MA. Location of conical intersections in solution using a sequential quantum mechanics/molecular dynamics method. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.06.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Garavelli M, Robb MA. Preface. Theor Chem Acc 2007. [DOI: 10.1007/s00214-007-0325-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Excited States of Conjugated Hydrocarbons Using the Molecular Mechanics - Valence Bond (MMVB) Method: Conical Intersections and Dynamics. Theor Chem Acc 2006. [DOI: 10.1007/s00214-006-0113-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Shurki A, Crown HA. Hybrid ab initio VB/MM Method − A Valence Bond Ride through Classical Landscapes. J Phys Chem B 2005; 109:23638-44. [PMID: 16375342 DOI: 10.1021/jp054913x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of a new hybrid (QM/MM) method, where the QM part is treated by ab initio valence bond (VB) theory is presented. This VB/MM method has the advantages of empirical VB (EVB) methodology but does not rely on empirical parameterization for the quantum part. The method implements embedding of the quantum region of each diabatic state separately, by treating the electrostatic interactions between QM and MM regions classically. Additionally, it assumes that changes of the off diagonal matrix element due to different environments are such that the overall resonance integral does not change. These assumptions are discussed in detail and the validity of the method is shown to be successful in three different bond dissociation processes, where bond dissociation as well as solvation energies compare very well with the experimental data.
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Affiliation(s)
- Avital Shurki
- Department of Medicinal Chemistry and Natural Products, Lise Meitner-Minerva Center for Computational Quantum Chemistry, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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Larsen DS, Vengris M, van Stokkum IHM, van der Horst MA, de Weerd FL, Hellingwerf KJ, van Grondelle R. Photoisomerization and photoionization of the photoactive yellow protein chromophore in solution. Biophys J 2004; 86:2538-50. [PMID: 15041690 PMCID: PMC1304101 DOI: 10.1016/s0006-3495(04)74309-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Dispersed pump-dump-probe spectroscopy has the ability to characterize and identify the underlying ultrafast dynamical processes in complicated chemical and biological systems. This technique builds on traditional pump-probe techniques by exploring both ground- and excited-state dynamics and characterizing the connectivity between constituent transient states. We have used the dispersed pump-dump-probe technique to investigate the ground-state dynamics and competing excited-state processes in the excitation-induced ultrafast dynamics of thiomethyl p-coumaric acid, a model chromophore for the photoreceptor photoactive yellow protein. Our results demonstrate the parallel formation of two relaxation pathways (with multiple transient states) that jointly lead to two different types of photochemistry: cis-trans isomerization and detachment of a hydrated electron. The relative transition rates and quantum yields of both pathways have been determined. We find that the relaxation of the photoexcited chromophores involves multiple, transient ground-state intermediates and the chromophore in solution does not generate persistent photoisomerized products, but instead undergoes photoionization resulting in the generation of detached electrons and radicals. These results are of great value in interpreting the more complex dynamical changes in the optical properties of the photoactive yellow protein.
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Affiliation(s)
- Delmar S Larsen
- Faculty of Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.
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Nonnenberg C, Grimm S, Frank I. Restricted open-shell Kohn–Sham theory for π–π* transitions. II. Simulation of photochemical reactions. J Chem Phys 2003. [DOI: 10.1063/1.1623743] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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