Determination of the H–D2 spherically averaged potential and the H–Ne potential from absolute integral cross-section measurements

Abstract

Absolute integral cross sections for the H–D2 and the H–Ne collisions were measured by means of atomic–hydrogen beam scattering for kinetic energies of the atom of 1.8–330 meV with high accuracy. Realistic potential models which have only two or three adjustable parameters were used for the interpretation of the data in order to remove arbitrariness of interpretation. The best fit potential for H–D2 has a well of depth ε = 2.02 meV at position rm = 3.43 Å, and crosses zero at r0 = 2.99 Å which agrees exactly with r0 obtained by Torello and Dondi from the D–H2 differential cross-section measurements. The best fit potential for H–Ne (ε = 1.46 meV, rm = 3.40 Å, r0 = 2.99 Å) is in good agreement with ab initio potentials calculated by Das et al. The low-energy repulsive part of the best fit H–D2 potential is consistent, in the internuclear distance region of 4a0⩽r⩽5a0, with recent theoretical results of Truhlar and Horowitz for the spherically symmetric term of the H–H2 potential. The best fit H–D2 potential is finally modified in the region of r⩽4.5a0 so that its extrapolation to the short distance region leads to Truhlar and Horowitz’s results for r⩽3.5a0.