Ab initio cluster study of the interaction of hydrogen with the GaAs(100) surface

The GaAs(100) surface is modeled, using a cluster to study the interaction with hydrogen. On the basis of ab initio theory including electron correlations, the most stable structures for the As-terminated surface with adsorbed hydrogen atoms are established. The optimized structure of the modeled cluster without the adsorbate is also obtained. From the computational results of total energy, the activation energy of the dissociation of the hydrogen molecule on the surface was estimated. The cluster with adsorbed hydrogen atoms is more stable than that without hydrogen, although the approach of the hydrogen molecule toward the surface causes an increase in the total energy.