Dielectric and Pressure Virial Coefficients of Imperfect Gases. II. CO2–Argon Mixtures

Abstract

Dielectric and pressure second virial coefficients of five mixtures and the pure gases have been determined at 49.7°C, the values for CO2 at 29.4°C. The pressure coefficients are in reasonably good agreement with values predicted from combining rule Lennard‐Jones parameters derived from viscosities of the pure gases. The large effect of quadrupole interaction energy on the dielectric coefficient of pure CO2 has been calculated numerically, and analytical treatments of the smaller effects of reaction fields of induced moments, quadrupole‐induced dipole energy, and anisotropy energy have also been made. These result in a calculated molecular quadrupole moment of CO2 of 4.3 × 10−26 esu cm2 from the data for pure CO2. For CO2–Ar pairs, the effects in addition to the direct quadrupole‐induced dipole contribution are much smaller, and the value 4.1 × 10−26 esu cm2 for the quadrupole moment of CO2 is derived from the dielectric coefficient. Both values are in good agreement with the Buckingham–Disch result and with other less direct estimates from infrared and microwave absorption and from pressure virial coefficients.