Third Virial Coefficient for the Kihara, Exp-6, and Square-Well Potentials

Abstract

The classical third virial coefficient, assuming pairwise additivity, has been calculated by numerical integration for the Kihara and exp‐6 potential functions. The nonadditive contribution, using the three‐body potential model of Midzuno and Kihara (modified in the case of nonsixth‐power attraction) has also been calculated numerically for the Kihara, exp‐6, and square‐well potentials. Results are tabulated for each potential model at 40 reduced temperatures from 0.50 to 100.0 and for a range of third parameter values. A comparison is made of the change in emphasis on intermolecular separation between the second and third virial coefficients.