Classical Collision Theoty of Atoms with Solid Surfaces Using the Langevin Equation

Abstract

The classical mechanical theory of gas-surface inelastic collisions of Zwanzig is developed to include the thermal motion of lattice atoms. The fluctuation-dissipation theorem is verified between the thermal motion of struck atoms and response functions. The energy exchange between impinging gas atoms and lattice vibration is calculated, which is compared to the result from the distorted wave Born approximation. The trapping (sticking) conditions of impinging atoms are obtained in the form of the critical trapping energy. It is shown that the equation of motion of the impinging atoms approximately coincides with the generalized Langevin equation. The effective potential and the friction coefficient,which appear in the Langevin equation, are calculated.