The effect of shape factor on the quantal collision integrals

Abstract

Quantal collision integrals taking into account the shape factor which represents a nonspherical repulsive part of molecular interactions have been evaluated by using the tabulations of collision integrals for the Lennard-Jones (12:6) potential. The angular part of the interactions has been averaged by assuming that the colliding particles maintain the same relative orientation during an encounter and that all relative orientations have equal probability. The results show that the shape factor has significant influence on the quantal collision integrals. Attempts have been made to interpret the viscosity and thermal diffusion factor data for H2 and D2 gases. Another important result of these calculations is that, contrary to earlier assumptions, it is necessary to consider the effect of shape factor on viscosity for the precise determination of quadrupole moment of these substances from second virial and viscosity data.