Title

Mixed Quantum/Classical Approach for Description of Molecular Collisions in Astrophysical Environments

Document Type

Article

Language

eng

Format of Original

5 p.

Publication Date

5-21-2015

Publisher

American Chemical Society

Source Publication

Journal of Physical Chemistry Letters

Source ISSN

1948-7185

Original Item ID

DOI: 10.1021/acs.jpclett.5b00496

Abstract

An efficient and accurate mixed quantum/classical theory approach for computational treatment of inelastic scattering is extended to describe collision of an atom with a general asymmetric-top rotor polyatomic molecule. Quantum mechanics, employed to describe transitions between the internal states of the molecule, and classical mechanics, employed for description of scattering of the atom, are used in a self-consistent manner. Such calculations for rotational excitation of HCOOCH3 in collisions with He produce accurate results at scattering energies above 15 cm–1, although resonances near threshold, below 5 cm–1, cannot be reproduced. Importantly, the method remains computationally affordable at high scattering energies (here up to 1000 cm–1), which enables calculations for larger molecules and at higher collision energies than was possible previously with the standard full-quantum approach. Theoretical prediction of inelastic cross sections for a number of complex organic molecules observed in space becomes feasible using this new computational tool.

Comments

Journal of Physical Chemistry Letters, Vol. 6, No. 10 (May 21, 2015): 1854-1858.