Curve fitting analysis of near-edge core excitation spectra of free, adsorbed, and polymeric molecules

Abstract

The quantitative analysis of the near-edge region of K-shell excitation spectra of free, chemisorbed, condensed, and polymeric molecules is undertaken using curve fitting procedures. The deconvolution of both x-ray absorption (NEXAFS) and electron impact near-edge excitation spectra is considered. Among the topics discussed are the line shape of resonances in the near-edge region, the line shape of the continuum steps, physical interpretations for the line shapes, and parameters describing core excitation spectral features, and background corrections for NEXAFS spectra. The goal of the work is to establish systematic procedures for analyzing near-edge spectra which allow peak positions to be consistently determined, and enable peak areas to be reliably obtained so that, e.g., the orientation of molecules can be determined from NEXAFS spectra. A more quantitative understanding of the features in near-edge spectra will also aid development of an understanding of the physical events underlying a near-edge spectrum.