Mj. Lochhead et Kl. Bray, HIGH-PRESSURE FLUORESCENCE LINE NARROWING OF EU(III)-DOPED SODIUM DISILICATE GLASS, Physical review. B, Condensed matter, 52(22), 1995, pp. 15763-15775
High-pressure fluorescence line narrowing (HPFLN) has been used to cha
racterize the local structure of Eu3+ ions in sodium disilicate glass
up to 210 kbar. HPFLN spectra, measured at 77 K, were analyzed using c
rystal-field theory. As pressure was increased from ambient to approxi
mately 40 kbar, a redshift of me D-5(0)<--F-7(0) excitation band was a
ccompanied by a simultaneous decrease in the Eu3+ site crystal-field s
trength and a lengthening of the fluorescence lifetime from approximat
ely 2.3 to 2.4 ms. These trends were reversed above 40 kbar, as crysta
l-field strength increased with pressure and lifetime decreased linear
ly to approximately 1.4 ms at 210 kbar. The D-5(0)<--F-7(0) excitation
band broadened significantly above 70 kbar and continued to shift red
above 150 kbar. HPFLN results are interpreted in terms of structural
changes in the silicate glass matrix and compression of the Eu3+ bondi
ng environment. Lifetime and intensity changes are attributed to a pre
ssure induced increase in the electron-phonon coupling to local vibrat
ions. Pressure-induced crystal-field effects are used to deduce charac
teristics of high- and low-crystal-field-strength sites in ambient pre
ssure glasses. Spectral and lifetime results for the sample released f
rom high pressure show that a new local Eu3+ structure is formed durin
g decompression.