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Ab initio study of the photochemistry of aminopyrimidine
Author(s) -
Zechmann Gunther,
Barbatti Mario
Publication year - 2008
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.21612
Subject(s) - maxima and minima , chemistry , coupled cluster , excited state , ab initio , complete active space , potential energy surface , excitation , field (mathematics) , configuration interaction , ab initio quantum chemistry methods , potential energy , quantum chemistry , computational chemistry , surface hopping , quantum , atomic physics , molecular physics , molecular dynamics , physics , basis set , molecule , density functional theory , quantum mechanics , mathematical analysis , mathematics , supramolecular chemistry , organic chemistry , pure mathematics
Complete active space self‐consistent field (CASSCF), multi‐reference configuration interaction calculations (MR‐CISD), and equation of motion coupled‐cluster with singles and doubles (EOM‐CCSD) calculations are presented in order to elucidate the photodeactivation pathways of 6‐aminopyrimidine after vertical excitation to the S 1 1 nπ* state. Vertical excitation energies are reported up to the S 7 state. Two S 1 excited state minima, both of 1 nπ* character, and three strongly puckered 1 ππ* minima on the crossing seam (MXS) between the S 0 and the S 1 potential energy surface were found. Nonadiabatic reaction paths are discussed by linearly interpolating between the two minima and all MXS, which explain and extend observations made in recent surface‐hopping dynamics CASSCF investigations [Barbatti and Lischka, J Phys Chem A 2007, 111, 2852]. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008