Polarisation of the luminescence from KI:Sn2+

Abstract
The dependence of the polarisation upon temperature and azimuthal angle are reported for the two emission bands excited by A-band absorption in KI:Sn2+. The results are interpreted in terms of a model in which the Jahn-Teller coupling is stronger than the spin-orbit coupling and the Sn2+ centre is perturbed by a next-nearest-neighbour charge-compensating cation vacancy. This model quantitatively describes the observed complex temperature dependence of the polarisation in terms of the kinetics of the emission decay and the energy level scheme produced by the perturbations.