抄録
The interrelation between the intrinsic emission bands of NaI and KI has been examined by observing changes of luminescence spectra and their decay profiles in mixed Na1−xKxI crystals at 10 K. As x is increased from 0 to 1, the π emission band of NaI changes continuously into the σ emission band of KI. Furthermore, the decay component with a long lifetime (∼100 ns) diminishes, while the component with a short lifetime (∼1.0 ns) intensifies. An emission band changing into the π band of KI appears above x=0.95. It is concluded that the self-trapped exciton (STE) responsible for the π band of NaI corresponds to that for the σ band, rather than the π band, of KI. Lattice configurations of initial states for these emission bands are briefly discussed in connection with the recent off-center model of the STE.
