Binary collision dynamics and numerical evaluation of dilute gas transport properties for potentials with multiple extrema

摘要

Prediction of gaseous transport properties requires calculation of Chapmanndash;Enskog collision integrals which depend on all possible binary collision trajectories. The interparticle potential is required as input, and for a variety of applications involving monatomic gases the Hulburtndash;Hirschfelder potential is useful since it is determined entirely from spectroscopic information and can accomodate the longhyphen;range maxima and minima found in many systems. Hulburtndash;Hirschfelder potentials are classified into five distinct types according to their qualitative binary collision dynamics, which in general can be quite complex and can exhibit rsquo;rsquo;double orbitingrsquo;rsquo;, i.e., a pair of orbiting impact parameters for a single energy of collision. The collision integral program of Orsquo;Hara and Smith has been revised extensively to accomodate all physical cases of the Hulburtmdash;Hirschfelder potential, and the required numerical methods are described and justified. The revised program substantially extends the range of potentials for which collision integrals can be calculated.