Quantum-mechanical study of vibrational relaxation of HF in collisions with Ar atoms

• DOI: 10.1063/1.1333704
• Publication Date: 2002-07-26T13:24:54Z
• Authors: Roman V. Krems; Nikola Marković; Alexei A. Buchach...; Sture Nordholm
• Keywords: Vibrational energy relaxation; Quantum number; Potential energy surface; Kinetic isotope effect

Vibrational relaxation cross sections and rate constants of HF(v=1) by Ar are calculated on a recent semiempirical potential energy surface (PES) [J. Chem. Phys. 111, 2470 (1999)] using the quantum-mechanical coupled states approach. Accurate theoretical estimations coefficients for vibrational at temperatures between 100 350 K obtained. The is shown to be quasiresonant character occur mostly two nearest rotational levels ground state. weak isotope effect after substitution HF DF investigated explained. HF(v,j=0), where v=1,2,3,4, increase significantly as v increases. In same calculations we observe dramatic multiple quantum transitions difference initial final falls in close resonance with collision energy. A comparison obtained from those performed infinite-order-sudden approximation proves crucial role molecular rotations relaxation. Finally, describe coupling excitation HF(v=1, j=0) reduced number open channels basis set show that it possible obtain converged results rotationally inelastic various v=1 neglecting all below v=1, j=0.