| Abstract
| - The optical properties of sol−gel synthesized porous silica excited by synchrotron radiation in the 4−10 eVrange of samples with different porosity at 8 K and room temperature are reported. The analysis of the ultravioletphotoluminescence indicate the contributions of two different emitting centers. The spectral and temporalcharacteristics of the two luminescence bands are reported: emission peaks at about 3.7 and 4.0 eV, excitationchannels around 5.4−5.7 and 6.2−6.5 eV, and mean lifetimes of about 17 and 2 ns, respectively. The analysisof the optical properties in samples with different porosity allows us to propose a silanol-related model forthe two centers.
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