Change of electronic structure and chemical composition on the surface of freshly prepared As(35)S(65) thin films caused by electron- and light irradiation have been studied by high-resolution X-ray photoelectron spectroscopy. The mechanisms of the induced transformations are compared. It is shown that light irradiation causes redistribution of chemical bonds without change in chemical composition. The products of such light-induced structural transformations were also identified by Raman spectroscopy in the volume of thin films. Electron irradiation changes chemical composition of the surface by creating an As-enriched layer due to the formation of As-O bonds. Anomalous increase of the similar to 10 eV band associated with non-bonding As 4s electrons was observed after light- and low dose e-beam irradiation. (C) 2008 Elsevier B.V All rights reserved.