A Device Concept for Demixing of Gas Species Based on Excitation of Internal Energy Modes

In this work a phenomenon arising from gas-wall interaction in rarefied regimes is presented and discussed. It is hypothesized that the effect of energy transfer between different modes of molecules scattered from walls can be used for demixing of different gas species. In order to study this effect, first a kinetic wall boundary model for diatomic gas molecules is devised. The model is derived by generalizing the Cercignani–Lampis gas-surface interaction kernel in order to embody the gas internal degrees of freedom (DoF). Here, opposed to the extensions of e.g. [5], energy exchange between different molecular modes are honored and thus different physical phenomena arising from inelastic gas–surface collisions can be observed.