Analytical calculation of the parameters of a molecular gas on a surface in the Smoluchowski problem (Q2760782)

An analytical solution of the classical Smoluchowski problem on the temperature jump in molecular (monoatomic, diatomic, and polyatomic) gases is presented. The gas occupies a half-space above a flat wall, with a constant temperature gradient and evaporation rate from the ''gas - condensed phase'' interface set far from this wall. The distribution function is explicitly constructed both in the half-space and at its boundary. Formulas for the concentration and temperature at the interface are derived; in the case of diatomic and polyatomic gases, formulas for temperatures determined by translational and rotational degrees of freedom of molecules are obtained. Numerical calculations are performed.