Abstract
The luminescence of very pure PbCl2 and PbBr2 single crystals has been studied at liquid nitrogen and liquid helium temperature. At 10 K, PbCl2, as well as PbBr2, exhibits three emission bands in the spectral region investigated, viz., one in the ultraviolet part of the spectrum, a second one in the blue and a third one in the red. In addition, PbCl2 shows a violet emission at 5 K. If, at 80 K, PbCl2 and PbBr2 crystals were exposed to ultraviolet radiation for one hour or more, a yellow emission appeared.