AN ALGEBRAIC VARIATIONAL APPROACH TO DISSOCIATIVE ADSORPTION OF A DIATOMIC MOLECULE ON A SMOOTH METAL-SURFACE

A general theoretical treatment employing a time-independent algebraic variational method (S-matrix Kohn variational method) for dissociative adsorption of a diatomic molecule on a smooth metal surface is presented. The time-independent scattering treatment using the S-matrix Kohn variational method naturally enables one to obtain accurate state-to-state reaction probabilities for dissociative adsorption of molecules on surfaces. In this paper, the S-matrix Kohn variational method is adapted to the 3D dissociative adsorption of H-2 on Ni (100) surface treated as a flat surface, and the state-to-state transition probabilities are obtained. The dependence of the dissociation probabilities on the initial rovibrational state of H-2(vjm) is examined. As a result of flat surface approximation, which conserves the rotation quantum number j(z) = m, the exchange symmetry of H-2 has an important consequence on the vibrations of the adsorbates. Specially if the rotational state of H-2 Satisfies the condition j + m = odd, the vibrational quantum number of two adsorbed hydrogen atoms must be different. The orientational effect of rotation is such that the in-plane rotation (m = j) is more favorable for molecular dissociation on surface than the out-of-plane rotation (m = 0).