| Abstract: | The influence of the lithium impurity on the formation and the stability of electronic colour centres is studied in NaF crystals. It is found that F- and M-absorption bands are somewhat displaced to the long wavelengthes when doping with lithium owing to the overlapping with FA- and MA-absorption bands. It is shown that the lithium impurity is stabilising one for the charged M-centres though their accumulation in the doped crystals occurs slower. The activation energy is determined for the thermal destruction of M+- centres. Thermal destruction of M+-centres assumed to be resulting from the anion vacancy removal. |
