Ion bombardment-induced decomposition of Li and Ba sulfates and carbonates studied by X-ray photoelectron spectroscopy

Abstract

Radiation damage to the surfaces of lithium and barium sulfates and carbonates under 4 ke V Ar + bombardment has been investigated by X-ray photoelectron Spectroscopy (XPS). Damage is readily observed at a dose of 1 × 10 16 ions cm −2 with saturation occurring over the range 2–8 × 10 17 ions cm −2. Both valence and core level XPS spectra indicate that, at the saturation dose, the basic sulfate and carbonate structures remain along with decomposition products. Both sulfur and carbon are preferentially lost from all four compounds and oxygen is preferentially lost from both Li compounds but not from the Ba compounds as a result of bombardment. The major decomposition products are the metal oxides with smaller quantities of carbides, sulfides, and SO n x− ( n = 3,2,1) species.