Combining rules

The combining rules (also known as mixing rules) for binary mixtures are variously given by

Berthelot rule

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \epsilon_{ij} = \sqrt{\epsilon_{ii} \epsilon_{jj}}}

Lorentz rule

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \sigma_{ij} = \frac{\sigma_{ii} + \sigma_{jj}}{2}}

See also Lennard-Jones model

Admur and Mason

For the second virial coefficient of a mixture (Ref. 1)

$B_{ij}={\frac {\left(B_{ii}^{1/3}+B_{jj}^{1/3}\right)^{3}}{8}}$

References

1. I. Amdur and E. A. Mason "Properties of Gases at Very High Temperatures", Physics of Fluids 1 pp. 370-383 (1958)