Photoelectron–Photofragment Coincidence Studies on the Dissociation Dynamics of the OH–CH₄ Complex

Journal Article · Thu May 30 00:00:00 EDT 2019 · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

DOI:https://doi.org/10.1021/acs.jpca.9b02441· OSTI ID:1755315

Benitez, Yanice ^[1]; Lu, Dandan ^[2]; Lunny, Katharine G. ^[1]; Li, Jun  ^[3]; Guo, Hua  ^[4]; Continetti, Robert E.  ^[1]

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1. Univ. of California, San Diego, La Jolla, CA (United States)
2. Chongqing Univ. (China)
3. Chongqing Univ. (China); Univ. Göttingen (Germany)
4. Univ. of New Mexico, Albuquerque, NM (United States)

Photoelectron-photofragment coincidence (PPC) spectroscopy was used to characterize the energetics and dynamics of the OH + CH₄ → H₂O + CH₃ reaction initiated by photodetachment of the OH^–(CH₄) anion complex. PPC measurements at a photon energy of 3.20 eV yielded stable (OH-CH₄ + e^–) and dissociative (OH + CH₄ (ν₁ or ν₃, v = 0, 1) + e^–) channels. The main channel is dissociation to OH + CH₄ + e^– with a low kinetic energy release (KER), peaking at 0.04 eV. Interpretation of the experimental results was supported by quantum chemistry and quasiclassical trajectory calculations. Here, the anion potential energy surface was constructed at the correlated coupled cluster singles, doubles, and perturbative triples level with augmented correlation consistent polarized valence triple-zeta basis set, and previously calculated neutral potential energy surfaces were used. Quasiclassical simulation of the dynamics of the OH-CH₄ complex was carried out by selecting the momenta and coordinates from the Wigner distribution for the anion, providing the starting point for 4000 trajectories on the neutral potential energy surface. In agreement with the experimental results, most of the trajectories yield slowly recoiling OH + CH₄ reactants while some are trapped in the entrance channel van der Waals well.

• Research Organization: Univ. of California, San Diego, La Jolla, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC)
• Contributing Organization: U.S. Air Force Office of Scientific Research, National Natural Science Foundation of China
• Grant/Contract Number: FG03-98ER14879; 1573027
• OSTI ID: 1755315
• Alternate ID(s): OSTI ID: 1813913
• Report Number(s): FA9550-15-1-0305; 21573027
• Journal Information: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Vol. 123, Issue 23; ISSN 1089-5639
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Photoelectron photofragment coincidence
hydroxyl radical
quasiclassical trajectory calculations
chemical reactions
photodetachment
energy
anions
mathematical methods