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.
Optical spectroscopy of Eu3+ ion as a tool for the study of dehydration process in silica gels
Ferrari;
1994
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
