
%0 Journal Article
%A Fielding, PE 
%T Colour centres in zircon containing both Eu<sup>3+</sup> and U<sup>4+</sup> ions
%J Australian Journal of Chemistry
%D 1970/08/01
%V 23
%N 8
%P 1513-1521
%K 
%R https://doi.org/10.1071/CH9701513
%U https://www.publish.csiro.au/paper/CH9701513 
%X Single crystals of zircon containing both Eu3+ and U4+ were grown from flux melts cooled at rates varying between 4º/hr and 2º/hr. Irradiation with u.v. develops colour centres only in those regions of a crystal containing Eu3+ and U4+. Fluorescence and absorption spectra measured at temperatures down to 77ºK show that these centres are similar in behaviour to F and F' centres in the alkali halides. They are thought to be related to an exchange coupled pair, U4+-02-Eu3+, but the experimental data permit only a description in terms of one-electron energy levels. The same basic behaviour is observed for zircon containing U4+ and any other lanthanide but some interesting differences are described for U4+, Dy3+. 
