title: Ab initio study on one-way photoisomerization of the maleic acid and fumaric acid anion radical system as a model system of their esters.
abstract: Potential energy surfaces (PESs) of the maleic acid anion radical (MA-*: cis isomer)/fumaric acid anion radical (FA-*: trans isomer) system as a model system of their esters have been studied in detail using CASSCF method. The results suggest the following: The photoisomerization is initiated with the H-C-C-H dihedral angle distortion [hydrogen out of plain (HOOP) motion] on the D1 PES. The C-C-C-C dihedral angle distortion occurs on the D0 PES after the deactivation from D1 to D0. A large fraction of the net motion along the isomerization coordinate occurs on the D0 PES. The D0 state is responsible for the one-way nature of the photoisomerization.
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Sumita
authors.forename: Kazuya
authors.initials: K
authors.lastname: Saito