DEFECT-INDUCED AND DISORDER-INDUCED ABSORPTION IN THE FAR INFRARED.
Loading...
Date
1967
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Defect-induced absorption: The far-infrared band-mode absorption of the systems $NaCl:Ag^{+}, NaCl:Cu^{+}, NaCl:Mg^{++}, NaCl:Ca^{++}, KCl:Cu^{+}$ and $KCl:Br^{-}$ will be discussed. Some of these systems show typical resonant band-modes while others yield only a broad absorption in the acoustic phonon region according to the density of phonon states. On doped KBr, the extent of the small acoustic-optical gap could be determined by means of the defect induced lattice absorption. Further experiments on KJ, doped with $OH^{-}$ and $OD^{-}$ respectively, have shown a series of sharp lines located in the acoustic-optical gap region which are interpreted as partly due to librational modes of the molecular ion defect in the host crystal and partly as localized translational modes of it. Disorder-induced absorption: Some phase transitions in solids are characterized by the onset of crystal disorder. Such disorder occurs for example at the Curie point of some ferroelectrics or at the melting point of crystals. Preliminary experimental results will be shown which demonstrate that these phase transitions can be studied by means of disorder induced absorption.
Description
Author Institution: Physikalisches Institut Universitat Freiburg, Freiburg, Germany.