Interpretation of the vibrational relaxation of H-2 in H-2 within the semiclassical effective mass approach

Abstract

The temperature dependence of the rate coefficients for vibrational relaxation of H-2 in neat H-2 is interpreted within the semiclassical effective mass approach. Across the temperature range of 80-3000 K, the experimental rate coefficients vary by five orders of magnitude and fall onto a strongly nonlinear Landau-Teller plot. This behavior is explained by the nonclassical nature of the energy release and by a substantial participation of rotation of the colliding partners in inducing the vibrational transition. A single fitting parameter, the optimal reduced mass, permits one to represent the temperature dependence of the rate coefficient within a factor of 2. This parameter is found to be close to that obtained from a simple model suggested by Sewell [J. Chem. Phys. 99, 2567 (1993)]. (c) 2007 American Institute of Physics.