“…The additional absorption bands situated in the domain between 350 and 450 nm were attributed to the generation of non-bridging oxygen ion center. Then, a noticeable change appears in the intensity of the UV-VIS bands centered at about 310 nm which corresponds to the Pb +2 ions with s 2 configuration [14,15,25]. For sample with x = 10 mol% Gd 2 O 3 , the number of [PbO 6 ] structural units and the number of non-bridging oxygen ion center attain maximum values, in agreement with FTIR and UV-VIS data, respectively.…”