Defect modes due to H− - D− pair impurities in KCl and KBr

Model calculations for H-impurity centres in alkali halides

“…The out-of-phase vibration is at the higher frequency for the L modes but at a lower frequency for the T~ and T~ modes. This correction is made implicitly in a later paper (Robert and de Souza 1974) but the initial incorrect assignments are reiterated by Gupta and Mathur (1980), whose calculations presumably make corresponding transpositions.…”

“…The measurements of local-mode frequencies for H-H-, D-Dand H-Dpairs in KC1 by de Souza and Liity (1973) have been analysed by these authors in terms of a simple model in which the impurities are treated as rigid ions connected to each other and to the walls of a rigid three-dimensional box which is taken to represent the host lattice. Green function methods with a shell-model representation of the host crystal have been applied to these cases by Gupta and Mathur (1980). Both of these approaches rely for their success upon choices made for effective force constants around the impurity.…”