抄録
It has been observed that the intensity of the π emission at 3.31 eV in KI increases sharply within an exciting pulse duration and temporarily further with a time constant (τH) of ∼1μs, then decreases with a conventional decay time (τS) of about 1.8μs after the excitation by a pulsed N2 laser above ∼70 K. The height of the absorption band at 1.2 eV due to the transition from the 3∑u+ state to a higher excited state of the relaxed excitons behaves also in the same way. Such temporal increases suggest temporal increase of the population of the self trapped excitons at the 3∑u+ state. From the temperature dependence of τH, τS and of the intensity of the emission, a higher excited state of the self trapped excitons, from which excitons re-relax further into the 3∑u+ state, is discussed.
