The photo-induced recombination of exciton-created lattice defects (F,H center pairs) was studied in crystals at low temperatures. Two different luminescence centers, with quasi-molecular structures, could be distinguished. One of them was the self-trapped exciton, while the other was thought to be the H-plus-electron center.

B.Berzina: Journal of Molecular Structure, 1995, 349, 269-72