Abstract: The 5-parameter Morse potential(5-MP) of the interactions between Cl atoms and Ni surfaces was constructed. The adsorption and diffusion of Cl atoms on Ni low index-surfaces were investigated with 5-MP in detail. All the critical characteristics of the system, such as adsorption site, adsorption geometry, binding energy, eigenvalues for vibration, etc. were obtained. The calculated results show that chlorine atoms are likely to be adsorbed on the high symmetry sites. Cl atoms locate on the four-fold hollow sites of the intact Ni(100) surface, while they tend to occupy three-fold sites on the Ni(111) surface. The four-fold hollow sites are the most stable adsorption sites on the Ni(110) surface for Cl, although the three-fold sites and the long-bridge sites are stable adsorption sites on the Ni(110) surface for the atoms of the first and second periods. For the Cl-Ni surface adsorption system, the surface binding energy of a Cl atom is relevant to the coarse degree of the cluster surface, and the binding energies have an order of Ni(111)＜Ni(100)＜Ni(110).

Key words: Cl-Ni system, 5-MP, Surface adsorption, Surface vibration