It was shown that, in the case of crystals that were doped with an 0.0001 mole fraction of Na+, a decrease in the symmetry of the crystalline lattice (that resulted from the application of uniaxial compression along the <100> and <110> directions) appreciably altered the stabilization process of interstitial H centers that appeared during the X-irradiation of a stressed crystal at 80K. Upon applying a stress, the long-range elastic attraction between H centers essentially disappeared; as reflected by a marked drop in the creation efficiency of Br3 centers. In this case, the H centers were stabilized due to an increase in the localization of H centers around the Na+ impurity ions. In unstressed crystals, this process was quite insignificant at the Na+ doping levels which were used. Unlike the migration of H centers, which became oriented and was facilitated by the application of a stress, the migration of electronic excitations was hindered, and effects were observed which could be explained by the faster self-trapping of electronic excitations in stressed crystals.

A.Z.Bekeshev, E.A.Vasilchenko, K.S.Shunkeev, A.A.Elango: Fizika Tverdogo Tela, 1996, 38[8], 2394-405 (Physics of the Solid State, 1996, 38[8], 1316-21)