DFT Simulation of Electron Spectra for Auger Electron and Photoelectron Spectra of Lithium Compounds

Abstract

(Li, O, F)-Auger electron, and X-ray photoelectron spectra (AES, VXPS) of solid lithium compounds (Li metal, LiCl, LiF, Li₂O) are simulated by deMon density functional theory (DFT) calculations using the model molecules of the unit cell. Calculated valence XPS, core-electron binding energies (CEBE)s, and Li-, O-, and F-KVV AES for the substances correspond considerably well to experimental results. For the calculation of VXPS, the observed spectra of Li₂O pellet with chemisorbed CO₂ almost show agreement with simulation curve of the valence XPS according to the model for the 1/1 ratio of Li₂O/Li₂CO₃. In the case of AES calculation, we analyze the experimental AES with our modified Auger electron kinetic energy calculation method which corresponds to the two final-state holes at the ground state and at the transition-state in DFT calculation by removing 1 and 2 electrons, respectively. Experimental KVV AES of the Li atom, and (O, F) KVV AES of (Li₂O and LiF) in the substances almost agree well to the AES calculated with maximum kinetic energies at the ground state, and at the transition-state, respectively.