T. Nishimura et al., SURFACE RELAXATION AND RUMPLING OF RBI(001) DETERMINED BY MEDIUM-ENERGY ION-SCATTERING, Surface science, 411(1-2), 1998, pp. 834-838
The surface relaxation and rumpling of RbI(001) were determined direct
ly by medium energy ion scattering using a new toroidal electrostatic
analyzer. Its energy resolution was estimated to be 1 x 10(-3), which
allows a layer-by-layer analysis of a near surface region. We measured
the angular spectra of the ion scattering yields for I- around the [0
11] axis in the (100) plane and around the [111] axis in the (110) pla
ne using well-collimated 80 keV He+ beams. The angular shifts of the s
cattering yield minima for I- of the second layer from those for I- of
the deeper layers, giving quantitative information about the surface
relaxation and rumpling. The present analysis revealed that the locati
on of the top Rb+ and I- ions was shifted by 0.080 +/- 0.033 Angstrom
toward the inside and by 0.001 +/- 0.014 Angstrom toward the vacuum si
de, respectively from the non-relaxed lattice position in the surface
normal direction. The results are compared with the theoretical calcul
ations based on shell models and a molecular dynamics simulation. (C)
1998 Elsevier Science B.V. All rights reserved.