Chemical effects on the intensity of Ti Kη(radiative auger satellite) X-ray fluorescence spectra

Abstract

Weak lines at the low-energy side of the stronger main line in X-ray fluorescence spectra are mostly due to the X-ray Raman effect or the radiative Auger effect (RAE). The RAE line in the vicinity of the Kβ1,3(K–M3,2) main line is called Kη(K–M2). X-ray fluorescence spectra of the Ti Kβη region were measured for Ti–Al alloys and metals. It was found that the Kη intensity is independent of the titanium concentration for Ti–Al alloys and compounds. Consequently, it is concluded that the Kη line is mostly due to the radiative Auger effect, and not to the X-ray Raman effect. The intensity modifications of the radiative Auger satellite due to the changes in the chemical state were observed using a conventional Bragg-type X-ray fluorescence spectrometer. The measured intensity ratio Kη/Kβ is approximately 1% of that of the main Kβ line for titanium, and increases in the order metal < fluoride < boride < carbide < nitride < oxides. The intensity is not significantly changed among the oxides [TiO2, TiO, Ti2O3, and TiO(acac)2]. It is concluded that the Kη satellite originates from K–M2,3M2,3(M2,3= 3p–1) transition, and that the abnormally weak satellite intensity of fluoride is due to the strong hybridization between the Ti 3p and the F 2s orbitals.