Theoretical ELNES spectra of Si-K, Si-L, N-K, and O-K edges of an intergranular glassy film model in β-Si3N4

Abstract

A realistic atomic model of an intergranular glassy film (IGF) between the prismatic faces of crystalline β-Si3N4 has been used for ab initio exploration of variations in electron energy loss near edge structure (ELNES) spectral response from each of the component elements and available edges. The computed ELNES spectra within the IGF region show substantial variability that sometimes defy expectation. Upon careful analysis, we have devised guidelines for comparison and interpretation of the spectra in terms of the local coordination and bonding environment. The bond lengths, bond angles, coordination number, and elemental types of the bonded atoms cannot be relied upon to systematically explain the computed variations. It is anticipated that the rise of ELNES spectral measurements with enhanced spatial and energy resolution that are performed in conjunction with atomic scale imaging techniques will require new methods to interpret observed results. The intent of this work is to make progress and stimulate others in that direction.