3rd International Conference Laser M2P

J. Phys. IV France 04 (1994) C4-569-C4-572
DOI: 10.1051/jp4:19944137

Optical spectroscopy of Eu³⁺ ion as a tool for the study of dehydration process in silica gels

A. PIAZZA¹, A. BOUAJAJ^{1, 2}, M. FERRARI¹, M. MONTAGNA³, R. CAMPOSTRINI⁴ and G. CARTURAN<sup>4

1</sup>  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

Abstract
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