JUMP LENGTH DISTRIBUTION IN MOLECULE-ON-SUBSTRATE DIFFUSION

A kinetic theory is presented to describe the occurrence of long jumps of adsorbed molecules in a one-dimensional periodic potential. Under the assumption of collisional energy exchange with substrate excitatio ns to be strong enough (greater than or similar to kT), the jump lengt h distribution is given by a simple analytic function of one parameter , the ratio of two characteristic times: the time of flight through a potential cell and the molecule-substrate relaxation time. It is stron gly dependent on this ratio. The theory offers the possibility to unde rstand the results of recent experiments. (C) 1998 Elsevier Science B. V. All rights reserved.