Interatomic distances for overlapping shells in disordered systems: Model-less approach

Abstract

The regularization method of solving ill-posed problem is used to determine five partial interatomic distances from combined two EXAFS spectra without building any model of atomic structure. The mathematical procedure and the experimental results of the EXAFS analysis for NicZn1-cO (c 0.0, 0.3, 0.5, 0.7, 1.0) solid solutions with the rock salt (rs) crystal structure synthesized from the binary oxide powders are discussed. The measurements were performed using synchrotron facilities (Russian Research Centre "Kurchatov Institute", Moscow). The Ni and Zn K absorption spectra were recorded in transmission mode at room temperature. It was shown the ideal rock salt lattice is distorted and long-range order exists only at the average (Vegard law).