“Mechanical Doping” of Polycrystalline Alkali Halides with Pb2+Ions

It is shown that Pb2+ions can be introduced into polycrystalline matrices of NaCl, KCl, KBr, KI, and KCl0.5Br0.5by mechanical treatment of powder mixtures of the relevant alkali halides (AH) with small quantities of PbCl2or PbO (up to a few dozens of molar ppm). The comparison of the adsorption spectra of the above materials pressed into transparent pellets with those of conventionally Pb2+-doped AH single crystals proves that due to mechanical stimulation the dopant enters into the AH matrix in the form of isolated Pb2+ions substituting for the original lattice cations. It is shown that mechanical treatment is also effective in preparing polycrystalline samples of some mixed alkali halides like KCl0.5Br0.5.