STATISTICAL-MODELS FOR STICKING AND DESORPTION - A TIME-SCALE ANALYSIS

The problem of sticking/desorption and in particular a detailed balance relation connecting both phenomena is investigated within the general framework of forward and backward Markov processes. We obtain an important generalization of results which were found using a Master equation in energy space. The basis for a description of adsorption and desorption is a time-scale analysis. We therefore calculate eigenvectors, eigenvalues and the sticking coefficient for a Smoluchowski equation and show that a well-defined slow component exists even if the friction force is strongly position dependent. The consequences of a more complicated long time behavior will be discussed in terms of a Master equation. We obtain a generalized detailed balance relation which may be of use for a qualitative explanation of the yet unsolved problem of rotational cooling in the system NO/Pt(111).