Selection of the Intermolecular Potential Function. III. From the Isotopic Thermal Diffusion Factor

A method developed previously to evaluate quantitatively the relationship between intermolecular potential functions and macroscopic properties is extended to the isotopic thermal diffusion factor. As before, the relationship between function families has been clarified. In particular, the insensitive temperature range, here about ${\text{2\hspace{0.17em}≤\hspace{0.17em}T*}}_{\text{12−6}}\text{\hspace{0.17em}≤\hspace{0.17em}4}$ , was found in which the data do not permit the selection of a potential function. The function families studied were the $\text{m–6}$ , Kihara, and exp‐6. A quantitative evaluation of the sensitivity of the thermal diffusion factor to the potential function is presented.