Anharmonic Correlations of the U-Center Local Mode with Phonons in the U-Center Sidebands

Abstract

In a recent paper¹⁾ discussed the influence of the an-harmonic broadening of the U-Center local mode on the sideband absorption. The main results are shifts of the maxima positions and a drastic reduction of the absorption in the gap region between the acoustic and optic modes. In addition the ratio of intensities of the first to the second maximum is increased, improving the agreement in the acoustic region between the experiment and a simple-theory which neglects the effect under consideration^{2) 3) 4)}. Results have been given for summation bands in KI and KBr containing U-Centers. In this paper we extend the investigation to KCl, NaBr and NaI.