Type-I or type-II behaviour of the FA centres in alkali halides has always been thought of as a feature dependent on the crystal lattice parameter and on the impurity size. We have found experimental evidence suggesting for the first time that both behaviours are present in RbCl:Li+, where the FA centre at low temperature (TŠ<Š15 K) exhibits a luminescence of type-I switching to type-II at higher temperature. This effect is probably related to the possibility for the Li+ ion of being, at high temperature, a mobile and off-centre ion. Both these conditions seem to be necessary for having a type-II behaviour.
Baldacchini, G., Giovenale, E., De Matteis, F., Scacco, A., Somma, F., Casalboni, M., et al. (1988). New luminescence of the FA centre in RbCl:Li+. EUROPHYSICS LETTERS, 7(7), 647-650 [10.1209/0295-5075/7/7/013].
New luminescence of the FA centre in RbCl:Li+
De Matteis, F.;Casalboni, M.;
1988-01-01
Abstract
Type-I or type-II behaviour of the FA centres in alkali halides has always been thought of as a feature dependent on the crystal lattice parameter and on the impurity size. We have found experimental evidence suggesting for the first time that both behaviours are present in RbCl:Li+, where the FA centre at low temperature (TŠ<Š15 K) exhibits a luminescence of type-I switching to type-II at higher temperature. This effect is probably related to the possibility for the Li+ ion of being, at high temperature, a mobile and off-centre ion. Both these conditions seem to be necessary for having a type-II behaviour.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
