M. Leone et al., LOCAL DYNAMIC PROPERTIES OF VITREOUS SILICA PROBED BY PHOTOLUMINESCENCE SPECTROSCOPY IN THE TEMPERATURE-RANGE 300-4.5 K, Journal of non-crystalline solids, 234, 1998, pp. 514-519
We report experimental data on the thermal dependence, from room tempe
rature to 4.5 K, of the photoluminescence activity in the spectral reg
ion between 4.0 and 4.5 eV, for different types of vitreous silica. Th
e three photoluminescence bands previously detected in this energy ran
ge, alpha(E), alpha(I) and alpha(R), are investigated by analyzing the
temperature dependence of their spectral moments. This method enables
us to obtain information on both the electronic properties of the chr
omophores responsible for the observed emissions and on the structural
and dynamic properties of their environment. Our results show that di
fferent point defects present different coupling constants with their
surroundings and that the pristine properties of the silica samples is
relevant in determining the structural heterogeneity and the mean fre
quencies of the vibrational modes that couple with the electronic tran
sition. (C) 1998 Elsevier Science B.V. All rights reserved.