Translational heating of D(2) molecules thermally desorbed from Si(100) and Ge(100) surfaces.

The translational energies of D(2) molecules thermally desorbed from the Si(100) and Ge(100) surfaces under a heating rate of 6 K/s have been measured. In contrast to the previous laser desorption study, results show a considerable translational heating; the observed translational temperature is about 3 times higher than the desorption temperature for both surfaces. This fact indicates that energy barriers for adsorption are present even in the desorption pathway. Detailed balance is applicable to the adsorption and desorption dynamics of hydrogen on the Si(100) surface.