Maximum-entropy spectral analysis of extended energy-loss fine structure and its application to time-resolved measurement

Abstract

A maximum-entropy method (MEM) is applied to analysis of extended energy-loss fine structure (EXELFS). The present MEM–EXELFS analysis allows us to derive a radial distribution function (RDF) free from non-existing ghost peaks even when the original data set includes relatively a considerable amount of statistical noise. This markedly shortens the integration time for spectrum acquisition and simplifies the numerical procedures necessary for the RDF analysis, in contrast with the conventional fast Fourier transform method. The method can open the possibility of in-situ or time-resolved experiments of dynamic structural changes of materials. Its application to the recrystallization process of an amorphous Si film has suggested that the crystallization starts with the recovery of the coordination number and bond lengths, followed by the recovery of the stable bond angles in local tetrahedral configurations.