A study of transferability of atomic background on EXAFS spectra of simple gaseous compounds of As

From EXAFS spectra of As and As₂O₃ vapors and arsine gas AsH3 the ab initio calculated structural signal is removed. The remainders comprise small absorption edges due to shake-up channels involving electrons from 3d or 3p subshell. With enhanced resolution, the edges reveal a fine splitting and a varying contribution of resonance channels, due to individual molecular energy-level structure of the samples. On the resolution level appropriate for routine EXAFS analysis the remainders coincide, representing a unique and transferable atomic absorption background for the range of As valence states spanned by the samples.