LUMINESCENCE PROPERTIES OF RARE EARTH ACTIVATED CADMIUM SULPHIDE IN RANGE 4000 TO 15000 CM-1

Microcrystalline powders of rare earth activated cadmium sulphide, with copper as a co‐dopant, are investigated for line emission spectra, where (excluding Pm) the rare earth is anyone of the series from Pr to Yb. Seven of the eleven rare earths investigated have line emissions in the range 4000 to 15 000 cm−1. All lines are attributable to trivalent rare earth ions and most are characterized by similar broad band excitation spectra. An explanation for the appearance or non‐appearance of line spectra is sought on the basis of models proposed by previous workers in which resonance transfer of energy occurs, after absorption at the copper site, to the associated rare earth ion. Copyright © 1969 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim