title: Factors Affecting the Branching Ratio of Photodissociation: Thiophenol Studied through Quantum Wavepacket Dynamics.
abstract: The photodissociation dynamics of thiophenol (PhSH) excited to the 1(1) ππ* state was investigated by time-dependent quantum wavepacket propagation within two-dimensional (2D) space consisting of the S-H bond and -SH torsion. We systematically studied the dependence of the branching ratio (Ã/X(~)) between the two electronic states of the phenylthiyl radical (PhS(.) ) on several factors of the 2D potential energy surfaces (PESs). The effect of a reduced initial barrier to the first ππ*/πσ* conical intersection (CI) was found to be marginal, whereas the effects of a reduced torsional barrier of -SH on the excited ππ* state and the mitigated slope of the πσ* PES between the first (ππ*/πσ*) and the second (πσ*/S0 ) CIs were noticeable. The effect of the slope on the branching ratio has never been previously noticed. It was shown that the branching ratio can be sufficiently above unity without pre-excitation of the torsion mode of -SH, which has been assumed so far.
authors.affiliation: Department of Chemistry, Gangneung-Wonju National University, Gangwon-Do 210-702 (Republic of Korea).
authors.forename: Heesun
authors.initials: H
authors.lastname: An
authors.affiliation: Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Republic of Korea).|Current address: Plasma Technology Research Center, National Fusion Research Institute (NFRI), Gunsan, Jeollabuk-do 573-540, (Republic of Korea).
authors.forename: Heechol
authors.initials: H
authors.lastname: Choi
authors.affiliation: Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Republic of Korea). yslee@kaist.ac.kr.
authors.forename: Yoon Sup
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Gangneung-Wonju National University, Gangwon-Do 210-702 (Republic of Korea). baeck@gwnu.ac.kr.
authors.forename: Kyoung Koo
authors.initials: KK
authors.lastname: Baeck
keywords: branching ratio; photochemistry; potential energy surfaces; thiophenol; wavepacket dynamics