ISSN:
1063-7834
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Eu-and Ce-Eu-containing quartz glasses obtained by a direct sol-gel-glass transition are investigated. It is discovered that the conversion of a xerogel into a glass leads to lowering of the symmetry of the Eu3+ optical centers from hexagonal to orthorhombic and a many-fold increase in the efficiency of the excitation of their luminescence through the charge-transfer band. In the co-activated glasses, the distortion of these centers is enhanced, and compound Ce4+-Eu3+ centers appear, in which the Eu(III) oxo complexes are characterized by cubic symmetry and by sensitization of the luminescence of the Eu3+ ions by photoreduced (Ce4+)− ions. Crystal-field theory shows that the coordination number of the cation in such oxo complexes is equal to 8. It is established that similar structural formations exist in annealed xerogels, but they are manifested spectroscopically only upon low-temperature shortening of the interatomic distances, as a result of which the sensitization indicated becomes possible.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.1130755
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