Fluorescence Spectra of Cuprous Halides at Low Temperatures

The spectrophotographs of the visible fluorescence spectra, of cuprous halides excited by cathode ray were taken at temperatures ranging from room to liquid oxygen temperature. In cuprous chloride, we observed a colour change of fluorescence, that is, green fluorescence observable at high temperatures which disappeared at about -85℃, and below this temperature red fluorescence appeared. The red band also existed at high temperatures with considerable intensity but was covered with a green band to the sense of eyes. In bromide and iodide, no considerable change was observed and only the red fluorescence appeared over a certain range of temperature