Chemisorption bond lengths of chalcogen overlayers at a low coverage by convergent perturbation methods

Abstract

The bond lengths and binding locations of the p (2×2) chalcogen (O, S, Se, and Te) overlayers on Ni(001) are investigated in detail by microscopic low−energy electron diffraction (LEED) calculations. Two convergent perturbation methods are used which are as accurate as equivalent exact calculations but which minimize the use of computation core storage and time. Normal and off−normal incidences are considered and eight partial waves are used in the calculations. The results show the p (2×2) O and S bond lengths are identical to those of the c (2×2) structures determined by Demuth et al. The larger chalcogens Se and Te form slightly different bond lengths (difference less than ±0.1 Å) from those determined for the c (2×2) overlayer structures.