Second Approximation to the Thermal Diffusion Factor on the Lennard-Jones 12 :6 Model

Abstract

Several collision integrals useful for the calculation of the second approximation to the thermal diffusion factor have been evaluated for the Lennard‐Jones 12:6 model and utilized to calculate [R_T]₂, the second approximation to the thermal separation ratio from the expressions developed by Mason for the exp‐six model. It has been shown that the difference between [R_T]₁ and [R_T]₂ for the 12:6 model is very small and does not vitiate the method developed by us elsewhere for calculating the force constants from the thermal diffusion data. These considerations have been applied to argon and the results compared with the experimental data. A simple empirical relation connecting [R_T]₁ and [R_T]₂ has been derived for the Lennard‐Jones 12:6 model.