The Third Virial Coefficient for Non-Polar Gases

Publisher Website
Google Scholar
Abstract
The third virial coefficient for non-polar gases has been calculated with great accuracy by means of punched-card techniques. The Lennard-Jones potential, with inverse twelfth-power repulsion and inverse sixth-power attraction, was used in the calculations. Excellent agreement between our computations and those of Kihara was obtained at very high temperatures; in the moderate temperature region our calculations agree moderately well with those of Montroll and Mayer and those of de Boer and Michels. A comparison with experimental data indicates fairly good agreement for the approximately spherical molecules argon, methane, and nitrogen. In other cases there are discrepancies suggesting deviations from the form of the interaction energy which we assumed. There is considerably difficulty in obtaining accurate third virial coefficients from the equation of state data. A method is suggested whereby the third virial coefficients for mixtures of gases may be estimated. The functions which are tabulated should be particularly useful for extrapolating the equation of state to very high temperatures, where no experimental data are available. The zero-pressure derivative of the Joule-Thomson coefficient with respect to pressure provides additional means for comparing our tabulated functions with experimental data, and the deviations are consistent with those discovered by comparison of the third virial coefficients themselves.

This publication has 21 references indexed in Scilit: