THERMAL DIFFUSION OF A HEAVY IMPURITY IN A LASER-IRRADIATED LIGHT GAS.

The diffusion of a heavy impurity in a nonequilibrium light gas is analyzed. The analysis is in good agreement with experiment. It is demonstrated that the thermal-diffusion constant increases when internal degrees of freedom of the heavy molecules are excited by a laser beam. The conditions that maximize this effect are discussed. Diffusion in the field of an acoustic wave excited in a light gas is also investigated. Numerical estimates show that this process has advantages over thermal diffusion for separation of the components of gas mixtures.