We report experimental data on two types of natural silica, differing in their OH content, irradiated with UV photons (4.66 eV)from a pulsed Nd:YAG laser. Irradiation induces a reduction of the absorption band at 5.12 eV and of the associated emissions at3.14 eV and 4.28 eV, ascribed to twofold coordinated Ge(@Ge) centers pre-existing in our samples. The bleaching is mainly due tothe post-irradiation conversion of @Ge into the paramagnetic H(II) center via trapping of a H atom. Comparison with literaturedata points out the peculiarities of silica with a low Ge concentration as regards UV-induced transformations.
|Numero di pagine||5|
|Rivista||Journal of Non-Crystalline Solids|
|Stato di pubblicazione||Published - 2004|
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