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Title: Far-infrared collision-induced absorption in rare gas mixtures: Quantum and semi-classical calculations

We compare calculations of the translational collision-induced spectra and their integrated intensities of both He–Ar and Ne–Ar collisional complexes, using the quantum mechanical and a semiclassical formalism. Advanced potential energy and induced dipole functions are used for the calculations. The quantum method used is as described previously [L. Frommhold, Collision-induced Absorption in Gases (Cambridge University Press, 1993 and 2006)]. The semiclassical method is based on repeated classical atom-atom scattering calculations to simulate an ensemble average; subsequent Fourier transform then renders the binary absorption coefficient as a function of frequency. The problem of classical calculations is the violation of the principle of detailed balance, which may be introduced only artificially in classical calculations. Nevertheless, it is shown that the use of classical trajectories permits a fairly accurate reproduction of the experimental spectra, comparable to the quantum mechanical results at not too low temperatures and for collisional pairs of not too small reduced mass. Inexpensive classical calculations may thus be promising to compute spectra also of molecular pairs, or even of polyatomic collisional pairs with anisotropic intermolecular interactions, for which the quantum approach is still inefficient or impractical.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Chemistry Department, Lomonosov Moscow State University, GSP-1, Vorobievy Gory, Moscow 119991 (Russian Federation)
  2. (Russian Federation)
  3. Physics Department, University of Texas at Austin, Austin, Texas 78712-1081 (United States)
  4. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, 3 Pyzhevsky per., 119017 Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
22253130
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ANISOTROPY; ATOM-ATOM COLLISIONS; DIPOLES; FOURIER TRANSFORMATION; FREQUENCY DEPENDENCE; INTERACTIONS; MIXTURES; POTENTIAL ENERGY; QUANTUM MECHANICS; SEMICLASSICAL APPROXIMATION; SPECTRA