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Title: Full-dimensional multi-state simulation of the photodissociation of thioanisole

The photodissociation of thioanisole is very interesting because the experiments of Lim and Kim provide evidence for mode-specific effects on the product distribution. They showed that, with a specific S–CH 3 stretching mode being excited as the reagent is excited to the S 1 electronic state, there is a sharp increase in the proportion of the ground-state product to the excited-state product. In this work, we report 78 011 full-dimensional semiclassical multi-state trajectories of the photodissociation process using the coherent switching with decay of mixing dynamics method. The potential surfaces and couplings are based on electronic structure calculations that include dynamic correlation through second order perturbation theory. We report results for four sets of initial conditions, one corresponding roughly to 0–0 excitation and three corresponding to exciting one vibrational mode, to look for mode-specific effects. The simulations show no significant mode-specific effect on the product energy distributions, but they do show an effect on the distribution of minimum-energy gaps in the trajectories and on the lifetime for dissociation. In particular, excitation of the S–CH 3 stretching mode leads to trajectories passing closer to the S 1-S 2 conical intersection and to shorter lifetimes. This provides a possible explanation of whymore » experimental results are different for excitation of this vibration« less
Authors:
ORCiD logo [1] ; ORCiD logo [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Inst.
Publication Date:
Grant/Contract Number:
SC0015997; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 147; Journal Issue: 4; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of New Mexico, Albuquerque, NM (United States); Univ. of Minnesota, Minneapolis, MN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Contributing Orgs:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 74 ATOMIC AND MOLECULAR PHYSICS; band gap; photodissociation; chemical compounds and components; reaction rate constants; electronic structure methods; chemical elements; zero point energy; perturbation theory; vibrational spectra; potential energy surfaces
OSTI Identifier:
1474045
Alternate Identifier(s):
OSTI ID: 1373329