Molecular dynamics of infrequent events: Thermal desorption of xenon from a platinum surface

Abstract

Molecular dynamics techniques are employed to compute the rate of thermal desorption of Xe atoms from a platinumsurface at temperatures between 100 and 2000 °K. A generalized Langevin approach is used to substantially reduce the number of degrees of freedom required to achieve an accurate description of the desorption process. A variety of techniques developed to improve the feasibility of simulating slow processes are explored. Using a ’’compensating potential’’ procedure, desorption rates can be computed efficiently even at temperatures for which the residence time of Xe on the surface is of the order of 1 sec (1014 vibrational periods).