Impurity-induced core-valence lumionescence: A new possibility for fast scintillators creation

The impurity-induced core-valence lumionescence (CVL) originating from the radioactive recombination os valence electrons with the uppermost core holes of the impurity is studied in a number of chlorides doped with cesium. A correlation is established between the spectra shape and the local symmetry of the nearest-neighbor anion environment of the CVL-active impurity cation. This proves the cluster nature of the emission mechanism. Cluster calcualtions of the impurity-induced CVL spectra are in good agreement with the experimental results thus supporting the validity of cluster approach to the CVL. Peculiarities of the impurity-induced CVL excitation mechanism are considered. The effect of energy transfer from hist matrix cations to CVL-active ones due to core excitation migration is discussed. Prospects of searching for efficient fast scintillators based on the impurity-induced CVL are examined.