Showing papers by "Yu Harabuchi published in 2014"
TL;DR: It is concluded that ππ*-excited cis-stilbene propagates primarily toward the twisted structural region due to dynamic effects, with partial branching to the DHP structural region via the flat-surface region around (S1)cis-min.
Abstract: On-the-fly dynamics simulations were carried out using spin-flip time dependent density functional theory (SF-TDDFT) to examine the photoisomerization and photocyclization mechanisms of cis-stilbene following excitation to the ππ* state. A state tracking method was devised to follow the target state among nearly degenerate electronic states during the dynamics simulations. The steepest descent path from the Franck–Condon structure of cis-stilbene in the ππ* state is shown to reach the S1-minimum of 4,4-dihydrophenanthrene (DHP) via a cis-stilbene-like structure (referred to as (S1)cis-min) on a very flat region of the S1-potential energy surface. From the dynamics simulations, the branching ratio of the photoisomerization is calculated as trans:DHP = 35:13, in very good agreement with the experimental data, trans:DHP = 35:10. The discrepancy between the steepest descent pathway and the significant trans-stilbene presence in the branching ratio observed experimentally and herein computationally is clarifie...
77 citations
TL;DR: The present approach combines the seam model function approach with the recently proposed single-component artificial force induced reaction method to find MECIs systematically, and requires neither a Hessian nor a derivative coupling vector.
Abstract: Locating accessible conical intersections (CIs), especially minimum energy CI (MECI) structures, near the Franck–Condon (FC) region is one of the most important tasks in theoretical analyses of pho...
60 citations
TL;DR: In trans-1,3-butadiene, the ultrafast relaxation from the doubly excited state 2(1)Ag and the corresponding recovery of the ground state 1( 1)Ag were observed simultaneously for the first time by time-resolved photoelectron spectroscopy (TRPES) using 29.5 eV high harmonic pulses.
Abstract: In trans-1,3-butadiene, the ultrafast relaxation from the doubly excited state 2(1)Ag and the corresponding recovery of the ground state 1(1)Ag were observed simultaneously for the first time by time-resolved photoelectron spectroscopy (TRPES) using 29.5 eV high harmonic pulses. The fast recovery of 1(1)Ag shows that the following dissociation upon photoexcitation takes place after returning to the ground state. At 427 fs after photoexcitation, only the ionization energy from the C═C σ bond was found to remain shifted. Accompanying theoretical calculations with an assumption of Koopmans' theorem show that the ionization energy of the C═C σ bond is modulated by vibrational excitation of the antisymmetric C═C stretching mode. TRPES by high harmonics can probe the changes in the molecular structure sensitively.
22 citations
TL;DR: A direct reaction pathway for water-gas shift reaction (WGSR) in gas phase, H2O + CO → H2 + CO2, was discovered by using anharmonic downward distortion following method as discussed by the authors.
Abstract: A direct reaction pathway for water–gas shift reaction (WGSR) in gas phase, H2O + CO → H2 + CO2, was discovered by using anharmonic downward distortion following method. The direct WGSR is accompan...
6 citations
08 Jun 2014
TL;DR: Femtosecond relaxation and photodissociation dynamics of 1,3-butadiene were investigated by time-resolved photoelectron spectroscopy with high harmonics pulses, probing the deeper molecular orbitals which are sensitive to the molecular structure.
Abstract: Femtosecond relaxation and picosecond photodissociation dynamics of 1,3-butadiene were investigated by time-resolved photoelectron spectroscopy with high harmonics pulses, probing the deeper molecular orbitals which are sensitive to the molecular structure.
1 citations
07 Jul 2014
TL;DR: In this article, the photodissociation dynamics of a cumulated dine molecule, 1,2-butadiene, were investigated by time-resolved photoelectron spectroscopy using a high harmonic.
Abstract: Ultrafast and photodissociation dynamics of a cumulated dine molecule, 1,2-butadiene, were investigated by time-resolved photoelectron spectroscopy using a high harmonic. In contrast with 1,3-butadiene, coherent oscillation by stimulated Raman process was observed prior to photodissociation.
1 citations
07 Jul 2014
TL;DR: Femtosecond relaxation and photodissociation dynamics of 1,3-butadiene were investigated by time-resolved photoelectron spectroscopy with high harmonics pulses, probing the deeper molecular orbitals which are sensitive to the molecular structure.
Abstract: Femtosecond relaxation and picosecond photodissociation dynamics of 1,3-butadiene were investigated by time-resolved photoelectron spectroscopy with high harmonics pulses, probing the deeper molecular orbitals which are sensitive to the molecular structure.
1 citations