ProfessorMichaelBearpark

Araujo M, Lasorne B, Magalhaes AL, Worth GA, Bearpark MJ, Robb MAet al., 2009, The molecular dissociation of formaldehyde at medium photoexcitation energies: A quantum chemistry and direct quantum dynamics study, JOURNAL OF CHEMICAL PHYSICS, Vol: 131, ISSN: 0021-9606

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• Citations: 44

Larkin SM, Vreven T, Bearpark MJ, Morokuma Ket al., 2009, The application of the ONIOM hybrid method to the cycloaddition reactions of bromo-substituted 2(H)-pyran-2-ones, Canadian Journal of Chemistry, Vol: 87, Pages: 872-879

We investigate the performance of Our own N-layered Integrated molecular Orbital and molecular Mechanics (ONIOM) hybrid computational method applied to Diels–Alder reactions of bromo-2(H)-pyran-2-ones, combining the B3LYP/6–31G(d) method with a variety of low-level methods. We show that ONIOM is able to reproduce full B3LYP calculations, including the prediction of the stereoselectivity, which requires accurate potentials. We focus on the various ways in which the performance and potential errors of ONIOM can be analyzed, and show that the best method combination depends on the property one is interested in.

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Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA, Nakatsuji H, Caricato M, Li X, Hratchian HP, Izmaylov AF, Bloino J, Zheng G, Sonnenberg JL, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Montgomery JA, Peralta JE, Ogliaro F, Bearpark M, Heyd JJ, Brothers E, Kudin KN, Staroverov VN, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, Tomasi J, Cossi M, Rega N, Millam JM, Klene M, Knox JE, Cross JB, Bakken V, Adamo C, Jaramillo J, Gomperts R, Stratmann RE, Yazyev O, Austin AJ, Cammi R, Pomelli C, Ochterski JW, Martin RL, Morokuma K, Zakrzewski VG, Voth GA, Salvador P, Dannenberg JJ, Dapprich S, Daniels AD, Farkas O, Foresman JB, Ortiz JV, Cioslowski J, Fox DJet al., 2009, Gaussian 09, Wallingford CT, Publisher: Gaussian, Inc.

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Blancafort L, Lasorne B, Bearpark MJ, Worth GA, Robb MAet al., 2009, Second-Order Analysis of Conical Intersections: Applications to Photochemistry and Photophysics of Organic Molecules, The Jahn-Teller Effect: Fundamentals and Implications for Physics and Chemistry, Editors: Köppel, Yarkony, Barentzen, Heidelberg, Publisher: Springer, Pages: 169-200, ISBN: 978-3-642-03431-2

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Montagnese T, Ogliaro F, Wilsey S, Bearpark MJet al., 2008, Inertial Effects on the Intramolecular Vibrational Energy Redistribution and Nonadiabatic Photoisomerization of a 2,3-Substituted 1,3-Butadiene: A Quasi-Classical CASSCF Dynamics Study, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 112, Pages: 13239-13243, ISSN: 1089-5639

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• Citations: 4

Lasorne B, Bearpark MJ, Robb MA, Worth GAet al., 2008, Controlling S₁/S₀ Decay and the Balance between Photochemistry and Photostability in Benzene: A Direct Quantum Dynamics Study, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 112, Pages: 13017-13027, ISSN: 1089-5639

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• Citations: 55

Hall KF, Vreven T, Frisch MJ, Bearpark MJet al., 2008, Three-Layer ONIOM Studies of the Dark State of Rhodopsin: The Protonation State of Glu181, JOURNAL OF MOLECULAR BIOLOGY, Vol: 383, Pages: 106-121, ISSN: 0022-2836

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• Citations: 39

Tokmachev AM, Boggio-Pasqua M, Bearpark MJ, Robb MAet al., 2008, Photostability via Sloped Conical Intersections: A Computational Study of the Pyrene Radical Cation, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 112, Pages: 10881-10886, ISSN: 1089-5639

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• Citations: 25

Tomasello G, Ogliaro F, Bearpark MJ, Robb MA, Garavelli Met al., 2008, Modeling the Photophysics and Photochromic Potential of 1,2-Dihydronaphthalene (DHN): A Combined CASPT2//CASSCF-Topological and MMVB-Dynamical Investigation, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 112, Pages: 10096-10107, ISSN: 1089-5639

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• Citations: 12

Araujo M, Lasorne B, Bearpark MJ, Robb MAet al., 2008, The photochemistry of formaldehyde: Internal conversion and molecular dissociation in a single step?, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 112, Pages: 7489-7491, ISSN: 1089-5639

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• Citations: 47

Bearpark MJ, Larkin SM, Vreven T, 2008, Searching for conical intersections of potential energy surfaces with the ONIOM method: Application to previtamin D, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 112, Pages: 7286-7295, ISSN: 1089-5639

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• Citations: 41

Blancafort L, Bearpark MJ, Robb MA, 2008, Computational modeling of cytosine photophysics and photochemistry: from the gas phase to DNA, Radiation Induced Molecular Phenomena in Nucleic Acids, Editors: Shukla, Leszczynski, Publisher: Springer, Pages: 473-492, ISBN: 978-1402081835

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Lasorne B, Sicilia F, Bearpark MJ, Robb MA, Worth GA, Blancafort Let al., 2008, Automatic generation of active coordinates for quantum dynamics calculations: Application to the dynamics of benzene photochemistry, JOURNAL OF CHEMICAL PHYSICS, Vol: 128, ISSN: 0021-9606

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• Citations: 37

Sicilia F, Blancafort L, Bearpark MJ, Robb MAet al., 2008, New algorithms for optimizing and linking conical intersection points, JOURNAL OF CHEMICAL THEORY AND COMPUTATION, Vol: 4, Pages: 257-266, ISSN: 1549-9618

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• Citations: 87

Prince PD, Bearpark MJ, McGrady GS, Steed JWet al., 2008, Hypervalent hydridosilicates: synthesis, structure and hydride bridging, DALTON TRANSACTIONS, Pages: 271-282, ISSN: 1477-9226

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• Citations: 46

Hall KF, Tokmachev AM, Bearpark MJ, Boggio-Pasqua M, Robb MAet al., 2007, Molecular mechanics-valence bond method for planar conjugated hydrocarbon cations, JOURNAL OF CHEMICAL PHYSICS, Vol: 127, ISSN: 0021-9606

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• Citations: 13

Bearpark MJ, Ogliaro F, Vreven T, Boggio-Pasqua M, Frisch MJ, Larkin SM, Morrison M, Robb MAet al., 2007, CASSCF calculations for photoinduced processes in large molecules: Choosing when to use the RASSCF, ONIOM and MMVB approximations, Journal of Photochemistry and Photobiology A: Chemistry, Vol: 190, Pages: 207-227

In this article, we compare and contrast the RASSCF, ONIOM and MMVB electronic structure methods for calculating relaxation paths on potential energy surfaces of the excited states of large molecules, and for locating any resulting conical intersections at which nonadiabatic decay can take place. Each method is treated here as an approximation to CASSCF, which we choose as our reference level of theory, but which becomes prohibitively expensive computationally for large molecules. Both MMVB and ONIOM are hybrid computational methods – combining different levels of theory in an energy plus derivatives calculation at a particular molecular geometry – but they differ fundamentally in that MMVB is a hybrid-atom method, whereas ONIOM is a hybrid-molecule method. We explain this distinction through four representative applications: the photostability of pyracylene (studied with CASSCF, RASSCF, MMVB); large geometry changes in the singlet excited states of triangulene (studied with MMVB); a model for interstitial nickel defects in a synthetic diamond lattice (studied with ONIOM CAS:UFF); and the photochemical [4 + 4] cycloaddition of cyclohexadiene to naphthalene (studied with ONIOM CAS:MMVB). We show that each method is more appropriate for a particular type of photochemical problem. This article is part perspective, part review, and contains new results for three multi-state or photoinduced processes in complex systems.

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Boggio-Pasqua M, Bearpark MJ, Robb MA, 2007, Toward a mechanistic understanding of the photochromism of dimethyldihydropyrenes, JOURNAL OF ORGANIC CHEMISTRY, Vol: 72, Pages: 4497-4503, ISSN: 0022-3263

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• Citations: 44

Sicilia F, Bearpark MJ, Blancafort L, Robb MAet al., 2007, An analytical second-order description of the S0/S1 intersection seam: fulvene revisited, Theoretical Chemistry Accounts, Vol: 118, Pages: 241-251

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Bearpark M J, Robb M A, 2007, Conical Intersection Species as Reactive Intermediates, Reviews of Reactive Intermediate Chemistry, Editors: Platz, Moss, Jr, Publisher: Wiley-Interscience, Pages: 379-414, ISBN: 978-0-471-73166-5

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Migani A, Bearpark MJ, Olivucci M, Robb MAet al., 2007, Photostability versus photodegradation in the excited-state intramolecular proton transfer of nitro enamines: Competing reaction paths and conical intersections, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 129, Pages: 3703-3713, ISSN: 0002-7863

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• Citations: 30

Sicilia F, Blancafort L, Bearpark MJ, Robb MAet al., 2007, Quadratic description of conical intersections: Characterization of critical points on the extended seam, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 111, Pages: 2182-2192, ISSN: 1089-5639

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• Citations: 69

Bearpark MJ, Blancafort L, Paterson MJ, 2007, Mapping the intersection space of the ground and first excited states of fulvene, MOLECULAR PHYSICS, Vol: 104, Pages: 1033-1038, ISSN: 0026-8976

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• Citations: 23

Hall KF, Vreven T, Frisch MJ, Bearpark MJet al., 2007, Three-layer ONIOM studies of Rhodopsin in the dark state: Shedding light on the protonation state of Glu-181, International Conference on Computational Methods in Science and Engineering, Publisher: AMER INST PHYSICS, Pages: 713-713, ISSN: 0094-243X

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Bearpark MJ, Ogliaro F, Vreven T, Boggio-Pasqua M, Frisch MJ, Larkin SM, Robb MAet al., 2007, CASSCF calculations for excited states of large molecules: Choosing when to use the RASSCF, ONIOM and MMVB approximations, International Conference on Computational Methods in Science and Engineering, Publisher: AMER INST PHYSICS, Pages: 583-+, ISSN: 0094-243X

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• Citations: 8

Hall KF, Boggio-Pasqua M, Bearpark MJ, Robb MAet al., 2006, Photostability via sloped conical intersections: A computational study of the excited states of the naphthalene radical cation, JOURNAL OF PHYSICAL CHEMISTRY A, Vol: 110, Pages: 13591-13599, ISSN: 1089-5639

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• Citations: 38

Lasorne B, Bearpark MJ, Robb MA, Worth GAet al., 2006, Direct quantum dynamics using variational multi-configuration Gaussian wavepackets, CHEMICAL PHYSICS LETTERS, Vol: 432, Pages: 604-609, ISSN: 0009-2614

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• Citations: 41

Bearpark MJ, Boggio-Pasqua M, Robb MA, Ogliaro Fet al., 2006, Excited states of conjugated hydrocarbons using the molecular mechanics-valence bond (MMVB) method: Conical intersections and dynamics, THEORETICAL CHEMISTRY ACCOUNTS, Vol: 116, Pages: 670-682, ISSN: 1432-881X

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• Citations: 33

Boggio-Pasqua M, Bearpark MJ, Ogliaro F, Robb MAet al., 2006, Photochemical reactivity of 2-vinylbiphenyl and 2-vinyl-1,3-terphenyl: The balance between nonadiabatic and adiabatic photocyclization, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 128, Pages: 10533-10540, ISSN: 0002-7863

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• Citations: 20

Blancafort L, Bearpark MJ, Robb MA, 2006, Ring puckering of cyclooctatetraene and cyclohexane is induced by pseudo-Jahn-Teller coupling, MOLECULAR PHYSICS, Vol: 104, Pages: 2007-2010, ISSN: 0026-8976

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• Citations: 27