Interpolation of virial coefficients

The paper presents a method for interpolation of the temperature dependence of the coefficients appearing in the virial equation of state. Regression of available data for a virial coefficient at high and low temperatures is used to formulate an approximant that captures the order-of-magnitude behaviour in these extremes. This behaviour is factored out of the data, and the resulting residual is subject to spline interpolation. The value of the virial coefficient at an interpolated temperature is recovered by multiplying by the approximant evaluated at the temperature of interest. The scheme is demonstrated through application to virial data for several model systems, and is shown to provide much more reliable results than direct interpolation performed on the unscaled virial-coefficient data.