Abstract
We report a study of dynamics and kinetics in physisorption of CH3Cl on an highly-oriented pyrolytic graphite (HOPG). The oriented molecular beam scattering was used to monitor the dynamical interaction of CH3Cl with HOPG in the zero coverage limit, demonstrating that the CH3Cl scattering intensity depends on the molecular orientation of the incident CH3Cl. The observed steric preference is not sensitive to the surface temperature. These results suggest that the moderate anisotropy in the interaction potential induces the molecular-orientation dependence of energy dissipation during the transient trapping into the physisorption well. On the other hand, the thermal energy atom scattering (TEAS) was used to probe the kinetics of thermal CH3Cl adsorption on HOPG during the coverage evolution. The desorption energy of CH3Cl on HOPG changes from 0.25 to 0.30 eV with increasing surface coverage, suggesting the attractive interaction between CH3Cl molecules on the surface.
