Experimental and theoretical X-ray K-spectra of sulfur of zincblende-based compounds AgGaS2-CdGa2S4-InPS4

The K-edge X-ray absorption spectrum of sulfur in AgGaS2, CdGa2S4, and InPS4 was investigated both experimentally and theoretically. The lattices of these compounds can be represented as chalcopyrite with various amounts of defectiveness. The spectra were obtained with an experimental resolution about 0.2 eV. To obtain the theoretical absorption spectrum, the FEFF7 high order multiple scattering code was used. The clusters considered contained 80-87 atoms; up to 624 multiple-scattering paths of the photoelectron were taken into account, with the highest order scattering equal to 6. A very good correspondence between the theoretical and experimental spectra was achieved when the energy dependent exchange energy was calculated according to the Dirac-Hara approximation. (C) 2001 Elsevier Science Ltd. All rights reserved.