Abstract
The decay of the BG emission in KCl: I has been measured after pulsed excitation of localized excitons by the two-photon absorption process with a N2 laser light. At 1.9 K, the luminescence decays with two exponential components: τs=8.0 ms and τf=120 μs. The decay time of the slow component, τs, begins to decrease at-4 K, and approaches rapidly to the constant value-180μs at high temperatures. The decay time of the fast component, τf, remains constant up to-9 K, where its intensity vanishes abruptly. In the range 10-14 K, a slow'build-up' appears at the initial stage of the emission decay. Its time constant τr (=47μs at 10 K) falls simply with the rise of temperature. These results, as well as temperature dependence of the yield of each component, are discussed in terms of changing populations within a zero-field-split triplet state of the hetero-nuclear relaxed exciton [ICl-(VK) +e].
