“…Concerning the radiation-induced Ag-related species, an optical absorption spectrum of the X-ray-irradiated PG:Ag was decomposed into five individual Gaussian bands, marked "A" to "E", with peaks at 225, 252, 270, 307 and 354 nm, respectively. These bands were, in turn, attributed to Ag + , Ag 3 + or Ag 3 2+ , Ag 2 + , Ag 2+ and Ag 0 centres, respectively, through various optical and thermal measurements [11][12][13]. Moreover, the excitation spectrum consisted of two different bands.…”