The influence of low temperatures on the thermal diffusion effect

Publisher Website
Google Scholar
Abstract
Measurements of thermal diffusion on the following gas mixtures at temperatures between 15° C. and - 190° C. are described: He - Ne; H2 - Ne; He - A; Ne - A; He - N2. The experiments confirm and extend the authors' previous work showing that there is a general tendency for kt to decrease at low temperatures. It is found, however, that for the pairs of gases He - Ne and H2 - Ne, with low liquefying points, the change in kt between 15° C. and - 190° C. is small. Chapman's theory is used to deduce approximate values of the laws of repulsive force operating between unlike molecules during collisions. At low temperatures molecules tend to become "softer" and their behaviour is less like that of rigid elastic spheres. The "hardest" molecules appear to show the smallest variation in kt. The influence of helium in this respect, on the value of kt for a mixture, is clearly shown.

This publication has 0 references indexed in Scilit: