Accelerated molecular dynamics simulation of temperature programmed desorption

An accelerated molecular dynamics scheme was developed to simulate thermal desorption of alkanes from the basal plane of graphite at experimentally relevant temperatures. The alkanes, which range in size from pentane to hexadecane, spanned the range of those studied experimentally. Simulations results of single molecules provided an explanation for the chain-length dependence of alkane desorption. This explanation was based on internal degrees of freedom that are activated in the longer alkane molecules but not in the shorter alkane chains. The role of coverage in alkane desorption energetics by looking at the desorption of pentane at varying coverage. The rates may differ by orders of magnitude depending on the structure and coverage of the pentane film. This is an abstract of a paper presented at the AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).