Ab initio study of hydrogen desorption from diamond C(100) surfaces

The desorption potential energies of a hydrogen molecule from hydrogenated diamond C(100) surfaces have been calculated by the ab initio pseudopotential method. We found that a dihydride surface is less stable than a monohydride surface and that hydrogen desorption can be expected to occur from the dihydride instead of the monohydride phase of a C(100) surface, from a detailed analysis of the activation energy for adsorption and desorption of hydrogen molecules from C(100) surfaces. The theoretical values of the desorption energies are in good agreement with the experimental ones.