Effusion and thermal transpiration in quantum statistics

Abstract

In a previous paper (Srivastava 1938) the author has considered the effusion phenomena in detail from the standpoint of relativistic quantum statistics. This paper will be hereafter referred to as paper I. In this, however, the effusion of the gas into vacuum was considered. In the present communication we have investigated in § 1 the molecular effusion of one gas into another at a different pressure but at the same temperature. In §§ 2-4 the effusion of one gas into another at a different temperature has been considered, giving rise to the phenomenon of thermal transpiration, and the relation between the pressures in the two chambers in the steady state has been calculated. Non-degenerate matter has been considered in § 2, degenerate matter in § 3, and effusion of degenerate into non-degenerate matter in § 4. The method adopted is similar to that utilized in paper I involving the use of the usual quantum-statistical formulae. For the sake of brevity we shall omit here the deduction of certain results and the various steps of mathematical simplification which have already featured in paper I and shall content ourselves by merely quoting the results.