Collision integrals for isotopic hydrogen molecules

Elastic collisions involving o−H2+p−H2 and p−H2+HD were studied. The molecules interacted with a Lennard-Jones type potential modified to include angular terms. A set of cross sections, Q(l), and collision integrals, Ω(l, 8) (T), were obtained for each system. Collision integrals and thermal diffusion factors were calculated for p−H2+HD both with and without the angle dependent terms in the potential. The cross sections showed a small degree of sensitivity to the angular terms in the potential and to differences in the reduced mass of the systems. The collision integrals were quite insensitive to the angle dependent terms of the potential. The calculated thermal diffusion factor for each H2+HD case differed from the experimental value by approximately a factor of 2.