An EHMO Studies of Dissociative Chemisorptions of H₂ on （111） Surfaces of Ni and Its Alloys

The extended Huckel molecular orbital method was used to gain an insight into the interactions of H₂ with seven atom clusters simulating （111） crystal surfaces of Ni and its alloys（Ni₆Cu, Ni₆Mn, Ni₄Cu₃, Ni₄Mn₃）. Based on our calculation results, we could make the following conclusions: （1） Impure atom（Cu, Mn） were located on the top Ni （111） surface 3CN adsorpt position, the adsorption energy（E_a） increases, and if in side of it, the adsorption energy decreases. （2） With the distance between H₂ and the clusters shortened, the ability of adsorpted H₂ of the clusters strengthened and the electron transferred from the clusters to σ_1s^* anti-bonding orbital of H₂.These conclusions are in agreement with experimental facts when available, and they have been explained on the basis of the electronic structure, bonding nature and adsorbed positions.