A study of transferability of atomic background on EXAFS spectra of simplegaseous 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 abs orption edges due to shake-up channels involving electrons from 3d or 3p su bshell. With enhanced resolution, the edges reveal a fine splitting and a v arying contribution of resonance channels, due to individual molecular ener gy-level structure of the samples. On the resolution level appropriate for routine EXAFS analysis the remainders coincide, representing a unique and t ransferable atomic absorption background for the range of As valence states spanned by the samples.