A determination of the atomic geometry of the CdS(112-0) surface by dynamical analysis of measured low-energy (35E 250 eV) electron-diffraction (LEED) intensities is reported. The analysis is performed on the average of two data sets, each of which includes fifteen diffracted beams. Intensities are measured from two different CdS surfaces cleaved in ultrahigh vacuum and cooled below 50 K. The measurements are made using a fast LEED data-acquisition system. The scattered intensities are calculated using a relativistic, energy-dependent Hara-exchange electron ion-core potential. The search for the best-fit structure is conducted with a combination of the x-ray R factor and integrated-intensity R factor. The best description of the experimental intensities by the calculated ones is obtained for a structure characterized by a bond-length-conserving relaxation of the surface Cd-S-Cd and S-Cd-S triplets by an angle =30°followed by a 0.1 contraction of the first layer toward the bulk. This structure is in quantitative agreement with predictions based on total-energy-minimization calculations for this surface.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics