Model calculations in dynamics at surfaces. Associative thermal desorption

A quantum mechanical model of associative thermal desorption of a diatomic molecule on a rigid potential energy surface consisting of two channels coupled by a ‘late’ separable potential, is solved exactly. The angle-resolved desorption fluxes of molecules in their ground, and first excited vibrational states are exhibited for a parameterization of the model representing N2/Re(0001). The substrate temperature is 1000 K. The distributions, which are forward peaked, narrow as the substrate temperature is raised, and the population of the excited state always exceeds the Boltzmann value. Rotational populations in desorbed molecules can also be handled.