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Conical Intersections and Low‐Lying Electronic States of Tetrafluoroethylene
Author(s) -
Mullinax J. Wayne,
Sokolov Alexander Yu,
Schaefer Henry F.
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402073
Subject(s) - conical intersection , chemistry , photoionization , excited state , atomic physics , rydberg formula , dihedral angle , potential energy , electronic structure , ground state , molecular physics , physics , computational chemistry , ionization , molecule , ion , hydrogen bond , organic chemistry
The low‐lying electronic states of tetrafluoroethylene (C 2 F 4 ) are characterized theoretically for the first time using equation‐of‐motion coupled cluster theory (EOM‐CCSD), and complete active space self‐consistent field (CASSCF) and second‐order perturbation theory (CASPT2). Computations are performed for vertical excitation energies, equilibrium geometries, minimum‐energy conical intersections, and potential energy curves along three geometric coordinates: 1) twisting of the FCCF dihedral angle, 2) pyramidalization of the CF 2 group, and 3) migration of a fluorine atom resulting in an ethylidene‐like (CF 3 CF) structure. The results suggest two relaxation pathways from the Rydberg‐3s excited electronic state to the ground state. These relaxation pathways are discussed in conjunction with the femtosecond photoionization spectroscopy results of Trushin et al. [ ChemPhysChem 2004 , 5 , 1389].