Resolution and Analysis of Low Temperature Luminescent Spectra of Bi and Pb Activated Solids of Simple Crystal Structure

Abstract

Experimental arrangements are described by which clearly resolved spectra have been obtained of the luminescence, at the temperature of liquid air, of seven different phosphors of simple crystal structure (cubic) and of mixed crystals. The main peaks in each case may be arranged in a band series. The vibration frequency in the lower state is nearly the same for the same host lattice with different activators. The energy of the electronic transition is determined both by the activator and the host crystal and there is a progression of decreasing energy in the series of simple crystals MgO, CaO, SrO, CaS, and in the order CaO, CaO-SrO with mixed crystals. The most probable transitions are from the lowest level of the upper state. There is evidence that self-excitation occurs and for the view that the luminescent centres are large.