THE ENERGETICS OF HYDROGENIC REACTIONS AT DIAMOND SURFACES CALCULATEDBY A LOCAL SPIN-DENSITY FUNCTIONAL THEORETICAL METHOD

The energetics of reactions thought to be important in the growth of C VD diamond have been studied in detail by performing calculations base d on the local spin-density functional theory. These reactions are: (i ) the abstraction of a hydrogen atom from a (111) diamond surface crea ting a surface dangling bond, and (ii) the formation of reconstruction bonds on a diamond (100) surface by the removal of hydrogen molecules . The results of two benchmark calculations are also given, namely hyd rogen abstraction from methane and hydrogen exchange with methane. The energetics of these reactions are found to be within 0.2 eV of the ex perimental values for barrier height and overall energy. Data for diam ond are less well known, but where comparisons are possible the accura cy of calculations seems to be similar. For hydrogen abstraction by at omic hydrogen from a (111) surface the estimated barrier is slightly l ess than 0.4 eV and overall is energetically neutral.