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Title: Nonadiabatic photodissociation dynamics of the hydroxymethyl radical via the 2 2 A(3 s) Rydberg state: A four-dimensional quantum study

Abstract

Here, the quantum mechanical nonadiabatic photodissociation dynamics of the hydroxymethyl (CH 2OH) radical in its lowest absorption band is investigated for the first time on a set of coupled diabatic potential energy surfaces determined by accurately fitting a large set of ab initio data. In this two-state approximation, only the ground and first excited states of CH 2OH, which are coupled by conical intersections, are included. The reduced-dimensional dynamical model includes the CO stretch, the COH bend, the HCOH torsion, and the O–H dissociation coordinate. The experimentally measured hydrogen atom kinetic energy distribution is satisfactorily reproduced. The calculated product state distribution of the H 2CO( X) fragment indicates strong vibrational excitation in the CO stretching mode, resulting from the relatively large difference in the C–O bond length between the ground and excited electronic states of CH 2OH due to the photo-induced promotion of an electron from the half-occupied π* CO antibonding orbital to a Rydberg orbital. In addition, the bimodal kinetic energy distribution is confirmed to originate from nonadiabatic transitions near the conical intersection along the O–H dissociation coordinate

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [1]
  1. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemistry and Chemical Biology
  2. Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Univ. of New Mexico, Albuquerque, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Contributing Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
OSTI Identifier:
1474046
Alternate Identifier(s):
OSTI ID: 1363703
Grant/Contract Number:  
SC0015997; AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 146; Journal Issue: 22; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; quantum chemical dynamics; photodissociation; chemical compounds and components; chemical elements; Rydberg states; absorption band; antibonding molecular orbital; bond length; vibrational spectra; potential energy surfaces

Citation Formats

Xie, Changjian, Malbon, Christopher, Yarkony, David R., and Guo, Hua. Nonadiabatic photodissociation dynamics of the hydroxymethyl radical via the 22A(3s) Rydberg state: A four-dimensional quantum study. United States: N. p., 2017. Web. doi:10.1063/1.4985147.
Xie, Changjian, Malbon, Christopher, Yarkony, David R., & Guo, Hua. Nonadiabatic photodissociation dynamics of the hydroxymethyl radical via the 22A(3s) Rydberg state: A four-dimensional quantum study. United States. doi:10.1063/1.4985147.
Xie, Changjian, Malbon, Christopher, Yarkony, David R., and Guo, Hua. Mon . "Nonadiabatic photodissociation dynamics of the hydroxymethyl radical via the 22A(3s) Rydberg state: A four-dimensional quantum study". United States. doi:10.1063/1.4985147. https://www.osti.gov/servlets/purl/1474046.
@article{osti_1474046,
title = {Nonadiabatic photodissociation dynamics of the hydroxymethyl radical via the 22A(3s) Rydberg state: A four-dimensional quantum study},
author = {Xie, Changjian and Malbon, Christopher and Yarkony, David R. and Guo, Hua},
abstractNote = {Here, the quantum mechanical nonadiabatic photodissociation dynamics of the hydroxymethyl (CH2OH) radical in its lowest absorption band is investigated for the first time on a set of coupled diabatic potential energy surfaces determined by accurately fitting a large set of ab initio data. In this two-state approximation, only the ground and first excited states of CH2OH, which are coupled by conical intersections, are included. The reduced-dimensional dynamical model includes the CO stretch, the COH bend, the HCOH torsion, and the O–H dissociation coordinate. The experimentally measured hydrogen atom kinetic energy distribution is satisfactorily reproduced. The calculated product state distribution of the H2CO(X) fragment indicates strong vibrational excitation in the CO stretching mode, resulting from the relatively large difference in the C–O bond length between the ground and excited electronic states of CH2OH due to the photo-induced promotion of an electron from the half-occupied π*CO antibonding orbital to a Rydberg orbital. In addition, the bimodal kinetic energy distribution is confirmed to originate from nonadiabatic transitions near the conical intersection along the O–H dissociation coordinate},
doi = {10.1063/1.4985147},
journal = {Journal of Chemical Physics},
number = 22,
volume = 146,
place = {United States},
year = {Mon Jun 12 00:00:00 EDT 2017},
month = {Mon Jun 12 00:00:00 EDT 2017}
}

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