Surface structure and dipole moments of RbI(001) determined by high-resolution medium-energy ion scattering

摘要

The surface structure of Rbl(001) was determined directly by means of medium-energy ion scattering (MEIS) with a monolayer depth resolution. The rumpled surface structure determined here was compared with semi-classical shell-model calculations. On the basis of a simple model regarding the lattice site ion as a point charge accompanied by a dipole moment, we evaluated the dipole moments of the top- and second-layer I- and Rb+ ions self-consistently from the relaxed lattice positions determined by means of MEIS and from the polarizabilities estimated systematically from experimental refraction data. The balance between a short-range force and a long-range coulombic one determined the equilibrium positions of the top- and second-layer ions; these are consistent with those derived by means of MEIS within the experimental uncertainties of 0.02 Angstrom. This indicates that the polarizablities derived from the refraction data and the interatomic (short-range) potentials of the Born-Mayer type are applicable. [References: 22]