APPLICATION OF THE 3-LEVEL MODEL - RISE AND DECAY KINETICS OF THE TEMPERATURE-DEPENDENT EMISSION OF METAL-IONS WITH S(2)-VALENCE ELECTRON CONFIGURATION

Temperature-dependent rise time and lifetime results, by measuring the photon emission in the temperature range 10-200 K, were obtained on c is-(NEt4)2[TeCl4Br2]2-(C2v) and [SeCl6]2 - (O(h)). The kinetics of exc itation and relaxation are described by a three-level model containing transition rate constants which are related to different symmetry sel ection rules between corresponding electronic levels. The transient em ission can be modified by varying the excitation pulse length. Besides a slow component in the luminescence decay-curve (0.5 ms at T = 12 K) a second, faster component can be detected. The amplitude ratio of th ese components can be increased by decreasing the excitation pulse len gth, which can be explained by assuming non-thermally equilibrated exc ited states. The results allow the assignment of the lowest levels whi ch arise from the excited sp electron configuration of the central ion .