Diffusion processes and interactions of hydrogen atoms in Pd

Abstract On the basis of the total energy obtained with the recursion method in the tight-binding framework, we discussed the adsorption and diffusion mechanism in the system of hydrogen atoms in Pd. Considering the relaxations of a few surface layers, we calculated the HH interaction energies, the metal-H binding energies per H atom, etc., inside and on the surface of palladium (0 0 1), which are in good agreement with the experimental data of Nernst and Brodowsky and of Harada. It was also shown that, in the HH bonding on the surface, the bonding parallel to the (0 0 1) surface is more repulsive than that normal to the surface. Two H atoms occupying the two neighboring octahedral sites in Pd is shown to be the most stable configuration.