Spectroscopic determination of ion-defect pair energies in KCl:Sm2+

Hitherto undetermined symmetry origins of fluorescence lines occurring in the KCl:Sm2+5D0→7F5 transition region are examined in terms of lifetime measurements. From relative intensity measurements of all the dominant lines observed in the entire D0→75FJ(0≤ J ≤ 6) fluorescence spectrum and experimentally determined effective equilibrium distribution temperature of 219°K, the binding energies of the nearest-neighbor [C2ν(1,1,0)] and next-nearest-neighbor [C4ν(2,0,0)] Sm2+−K+ vacancy pairs are found to be −0.45 and −0.39 eV, respectively. At ordinary temperatures, the dominant sites, in the order of relative importance, are the C2ν(1,1,0), Cs(2,1,1), and C4ν(2,0,0) pairs. This observation is interesting in view of the predominance of the C4ν(2,0,0) site in the KCl:Sr2+ and KCl:Mn2+ systems.