DETERMINANTS OF SURFACE ATOMIC GEOMETRY - THE CUCL(110) TEST CASE

The atomic geometry of the CuCl(110)-(1 x 1) surface is determined by dynamical analysis of low-energy electron-diffraction intensities. This surface undergoes a relaxation characterized by a approximately 30-degrees Cu-Cl surface bond rotation, a 0.15 angstrom contraction of the top-to-second layer distance, and a 0.4 angstrom horizontal displacement of Cl relative to Cu. The relaxation is consistent with the "universal" structure deduced from the analysis of cleavage surfaces of tetrahedrally coordinated III-V and II-VI compounds, thereby revealing that this feature of the structure does not depend significantly on the ionicity of the compound.