Second Virial Coefficient of Polar Gases

The theoretical expressions for the second virial coefficient, B(T), are derived for the (18–6-3) Stockmayer potential Φ(r)=4ε[(σr)18−(σr)6]−μ2r3g(θ1,θ2,φ),where g(θ1, θ2, φ) = 2 cos θ1 cos θ2 − sin θ1 sin θ2 cos φ, and also according to the (28–7-3) potential. Tables of the reduced virial coefficient are given as a function of the reduced temperature for the (18–6-3) potential, and experimental B(T) data are interpreted for a number of gases. The potential parameters are reasonable and reproduce the B(T) data within the limits of experimental errors. The point dipole polarizable model is also considered.