Premium
Photodeactivation paths in norbornadiene
Author(s) -
Antol Ivana
Publication year - 2013
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.23270
Subject(s) - conical intersection , rydberg formula , excited state , norbornadiene , ab initio , potential energy , configuration interaction , avoided crossing , ground state , atomic physics , chemistry , valence (chemistry) , multireference configuration interaction , singlet state , population , physics , ionization , quantum mechanics , ion , biochemistry , demography , sociology , catalysis
The first high level ab initio quantum‐chemical calculations of potential energy surfaces (PESs) for low‐lying singlet excited states of norbornadiene in the gas phase are presented. The optimization of the stationary points (minima and conical intersections) and the recalculation of the energies were performed using the multireference configuration interaction with singles (MR‐CIS) and the multiconfigurational second‐order perturbation (CASPT2) methods, respectively. It was shown that the crossing between valence V 2 and Rydberg R 1 states close to the Franck–Condon (FC) point permits an easy population switch between these states. Also, a new deactivation path in which the doubly excited state with (π 3 ) 2 configuration (DE) has a prominent role in photodeactivation from the R 1 state due to the R 1 /DE and the DE/V 1 conical intersections very close to the R 1 and DE minima, respectively, was proposed. Subsequent deactivation from the V 1 to the ground state goes through an Olivucci–Robb‐type conical intersection that adopts a rhombic distorted geometry. The deactivation path has negligible barriers, thereby making ultrafast radiationless decay to the ground state possible. © 2013 Wiley Periodicals, Inc.