Knowledge Bank

Using a Perkin Elmer 112-G Fore-Prism Grating Spectrophotometer, infrared spectra of the local mode vibration of U-centers in KBr were obtained at temperatures as low as $12\circ K$ . These spectra exhibited varying abundances of side bands in the region $\pm 30$ $cm-1$ from the main band, and appear to be a function of the method of preparation of these U-center crystals. These side bands are not resolved at temperatures above $50\circ K$ . Studies of the main bandwidth as a function of temperature agree with results of previous investigators for some samples, but deviate sharply for others.