LUMINESCENCE OF KCLBI3-ABSORPTION BAND( EXCITED AT THE X)

The emission from KCl:Bi3+ excited in the X absorption band (i.e. betw een the A and B absorption bands) was measured as a function of temper ature. The polarized emission spectrum and the angular dependence of p olarization ratio were also investigated. The X-band excitation produc es two emission bands peaking at 345 and 395 nm, the centres of which are not the same. The loosely bonded Cl- ion arising from the substitu tion of Bi3+ ions into the KCl lattice is assumed to be the colour cen tre for the X-band emission. The definitive assignment of the two emis sion bands is presented in terms of the relaxed excited states of the perturbed Cl- ion, in which the Jahn-Teller interaction coupling to th e B1 and B2 vibronic modes is taken into account.