SURFACE MIGRATION AS A DETERMINATE FACTOR OF THE STICKING COEFFICIENTDERIVED FROM THE CHEMISORPTION MODEL

A chemisorption process model has been developed and a sticking coeffi cient has been formulated by taking the surface migration of physisorb ed particles into account. This model incorporates Langmuir's model fo r use when the migration barrier is infinite, and the standard precurs or model for use when dealing with a bare surface. The migration of in cident particles was found to make the sticking coefficient independen t of the surface coverage at low temperatures (approximate to 100 K). At higher temperatures, the migration appears to be a hidden parameter in the chemisorption process. The effect of migration can probably be confirmed, even at room temperature, by analyzing the chemisorption u sing free radicals. (C) 1995 American Institute of Physics.