title: Theoretical study on the photochromic cycloreversion reactions of dithienylethenes; on the role of the conical intersections.
abstract: The mechanism of the photochromic cycloreversion reactions is theoretically examined in a model system of dithienylethenes by means of the CASSCF and CASPT2 methods. The structures of its conical intersections (CIs), which are the branching points of the internal conversions, were obtained. The analyses of the minimum energy paths from the Franck-Condon states and the CI points suggest that the cycloreversion reaction occurs during the intramolecular vibrational energy redistribution (IVR) toward the quasi-equilibrium on the 2A state. The current study of the model system will provide a basic insight for the photochromic molecular design.
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Asano
authors.forename: Akinori
authors.initials: A
authors.lastname: Murakami
authors.forename: Takao
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Alexander
authors.initials: A
authors.lastname: Goldberg
authors.forename: Dominique
authors.initials: D
authors.lastname: Guillaumont
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yabushita
authors.forename: Masahiro
authors.initials: M
authors.lastname: Irie
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Nakamura