Type-I or type-II behaviour of the F A 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 F A centre at low temperature ( T < 15 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 F A Centre in RbCl:Li +. EUROPHYSICS LETTERS, 7(7).
New Luminescence of the F A Centre in RbCl:Li +
DE MATTEIS, FABIO;CASALBONI, MAURO;
1988-01-01
Abstract
Type-I or type-II behaviour of the F A 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 F A centre at low temperature ( T < 15 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.
