Careful inspection of the color of the samples and together with overall optical spectra indicates that no distinctive conclusion about the various specific states of the different TM ions.
The most important result is that the extended UV-near visible bands due to collective absorption of trace iron impurities (Fe3+ ions) and absorption of Bi3+ ions are highly prominent and superimpose or interfere almost all the spectral features from 200 to 500 nm.
The detailed interpretation of optical absorption spectra of 3d TMsdoped samples before and after gamma irradiation can be summarized as follows: