J. Phys. IV France 04 (1994) C4-569-C4-572
Optical spectroscopy of Eu3+ ion as a tool for the study of dehydration process in silica gelsA. PIAZZA1, A. BOUAJAJ1, 2, M. FERRARI1, M. MONTAGNA3, R. CAMPOSTRINI4 and G. CARTURAN4
1 CNR, Centro di Fisica degli Stati Aggregati ed Impianto Ionico, via Sommarive 14, 38050 Povo (TN), Italy
2 Physico-Chimie des Matériaux Luminescents, URA 172 du CNRS, Université Lyon I, 43 bd du 11 Novembre 1918, 69622 Villeurbanne, France
3 Dipartimento di Fisica, Università di Trento, via Sommarive 14, 38050 Povo (TN), Italy
4 Dipartimento di Ingegneria dei Materiali, Università di Trento, 38050 Mesiano (TN), Italy
The structural modification induced by dehydration in optical silica gel has been studied using the spectroscopy of Eu3+ ion. The samples, doped with molar ratio Eu/Si = 0.01:1, were heated for 48 hours at different temperatures from 60 °C to 200 °C. Information on the dinamical properties of the local environment of the Eu3+ were obtained both by fluorescence and excitation measurements at T=11 K. The analysis of the 5D0 → 7F0 transition appears of particular relevance in this study, because the transition is between J=0 states and does not present internal structure. Its inhomogeneous linewidth gives a measure of the energy distribution of the different Eu3+ sites. Site selection spectroscopy was performed by exciting into the 5D1 state. Three different sets of sites were found. The phonon sidebands of the 5D0 ← F0 and 5D1 ← 7F0 transitions were observed in the excitation spectra.
© EDP Sciences 1994