SIMS Study on Ion Impact Desorption of Water from Silica Gel

Previous studies on the radiation chemical reactions of CO-H₂ mixture [1], CH₄ [2], and CO-H₂O mixture [3] in the presence of various solid catalysts revealed that some insulators such as silica gel and alumina exhibit catalytic activity for the reactions under electron beam irradiation. Although such activity of insulators has been ascribed to transfer of radiation energy from insulators to gases adsorbed on their surfaces, the mechanism of energy transfer is not well understood at present. In order to shed some light on the mechanism, we have initiated the studies of fundamental processes which take place at gas/solid interfaces when energetic electrons or ions impinge on the surfaces of solids, especially insulators, covered with gases, using a combined surface analysis system of AES/SIMS. This paper describes the results on Ar+ ion impact desorption of water from silica gel as studied by SIMS.