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Title: Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H{sub 2}O + He system

Abstract

The mixed quantum/classical theory (MQCT) for inelastic molecule-atom scattering developed recently [A. Semenov and D. Babikov, J. Chem. Phys. 139, 174108 (2013)] is extended to treat a general case of an asymmetric-top-rotor molecule in the body-fixed reference frame. This complements a similar theory formulated in the space-fixed reference-frame [M. Ivanov, M.-L. Dubernet, and D. Babikov, J. Chem. Phys. 140, 134301 (2014)]. Here, the goal was to develop an approximate computationally affordable treatment of the rotationally inelastic scattering and apply it to H{sub 2}O + He. We found that MQCT is somewhat less accurate at lower scattering energies. For example, below E = 1000 cm{sup −1} the typical errors in the values of inelastic scattering cross sections are on the order of 10%. However, at higher scattering energies MQCT method appears to be rather accurate. Thus, at scattering energies above 2000 cm{sup −1} the errors are consistently in the range of 1%–2%, which is basically our convergence criterion with respect to the number of trajectories. At these conditions our MQCT method remains computationally affordable. We found that computational cost of the fully-coupled MQCT calculations scales as n{sup 2}, where n is the number of channels. This is more favorable than themore » full-quantum inelastic scattering calculations that scale as n{sup 3}. Our conclusion is that for complex systems (heavy collision partners with many internal states) and at higher scattering energies MQCT may offer significant computational advantages.« less

Authors:
 [1];  [2];  [3];  [1]
  1. Chemistry Department, Wehr Chemistry Building, Marquette University, Milwaukee, Wisconsin 53201-1881 (United States)
  2. (France)
  3. PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon (France)
Publication Date:
OSTI Identifier:
22308406
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 141; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOM-MOLECULE COLLISIONS; ATOMS; CROSS SECTIONS; INELASTIC SCATTERING; MOLECULES; WATER

Citation Formats

Semenov, Alexander, PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon, Dubernet, Marie-Lise, and Babikov, Dmitri, E-mail: dmitri.babikov@mu.edu. Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H{sub 2}O + He system. United States: N. p., 2014. Web. doi:10.1063/1.4895607.
Semenov, Alexander, PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon, Dubernet, Marie-Lise, & Babikov, Dmitri, E-mail: dmitri.babikov@mu.edu. Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H{sub 2}O + He system. United States. doi:10.1063/1.4895607.
Semenov, Alexander, PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon, Dubernet, Marie-Lise, and Babikov, Dmitri, E-mail: dmitri.babikov@mu.edu. Sun . "Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H{sub 2}O + He system". United States. doi:10.1063/1.4895607.
@article{osti_22308406,
title = {Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H{sub 2}O + He system},
author = {Semenov, Alexander and PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon and Dubernet, Marie-Lise and Babikov, Dmitri, E-mail: dmitri.babikov@mu.edu},
abstractNote = {The mixed quantum/classical theory (MQCT) for inelastic molecule-atom scattering developed recently [A. Semenov and D. Babikov, J. Chem. Phys. 139, 174108 (2013)] is extended to treat a general case of an asymmetric-top-rotor molecule in the body-fixed reference frame. This complements a similar theory formulated in the space-fixed reference-frame [M. Ivanov, M.-L. Dubernet, and D. Babikov, J. Chem. Phys. 140, 134301 (2014)]. Here, the goal was to develop an approximate computationally affordable treatment of the rotationally inelastic scattering and apply it to H{sub 2}O + He. We found that MQCT is somewhat less accurate at lower scattering energies. For example, below E = 1000 cm{sup −1} the typical errors in the values of inelastic scattering cross sections are on the order of 10%. However, at higher scattering energies MQCT method appears to be rather accurate. Thus, at scattering energies above 2000 cm{sup −1} the errors are consistently in the range of 1%–2%, which is basically our convergence criterion with respect to the number of trajectories. At these conditions our MQCT method remains computationally affordable. We found that computational cost of the fully-coupled MQCT calculations scales as n{sup 2}, where n is the number of channels. This is more favorable than the full-quantum inelastic scattering calculations that scale as n{sup 3}. Our conclusion is that for complex systems (heavy collision partners with many internal states) and at higher scattering energies MQCT may offer significant computational advantages.},
doi = {10.1063/1.4895607},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 11,
volume = 141,
place = {United States},
year = {2014},
month = {9}
}