Temperature Dependence of the Nuclear Quadrupole Relaxation Rate in Silver and Sodium Halide Crystals

Thin epitaxial AgBr(001) films grown on NaCl: Growth, surface structure, and phonon dynamics

“…6, the Debye temperature of the AgBr͑001͒ surface was calculated to be ⌰ D (AgBr)ϭ95 K for the estimated He-surface potential well depth of Dϭ15.2 meV. As expected, this is significantly lower than the Debye temperature of AgBr bulk, which was calculated by Yamanishi et al 8 to be ⌰ D bulk ϭ168 K. The surface thermal expansion coefficient of 20 ML thick AgBr͑001͒ film was determined from a series of angular distributions along the ͓100͔ direction as a function of the crystal temperatures. From each angular distribution, the reciprocal G vector at a given temperature was extracted and then converted to the surface lattice constant a, which is plotted in Fig.…”

“…Thus, the observation of a rather low corrugation of the AgBr͑001͒ surface is consistent with a stronger covalent bonding as compared to pure ionic crystals such as NaCl and LiF ͑ionicity is about 95-100 %͒. 7,8 To determine the surface Debye temperature ⌰ D of AgBr͑001͒, the specular peak intensity was measured as a function of the crystal temperature T s as shown in Fig. 6.…”

“…In contrast to the alkali halides, in which the bonds between ions have nearly 100% ionic character, in silver halides the pure ionic interactions are not so pronounced and the distance between neighboring ions aЈ(Ag ϩ ϪBr Ϫ ) is significantly less than the sum of the ionic radii ͓r Ag ϩϩ r Br Ϫϭ 1.26ϩ1.96ϭ3.22 Å; aЈ(Ag ϩ ϪBr Ϫ ) ϭ2.88 Å͔. The degree of ionic bonding in AgBr is listed in Kittel's book 7 as 84% and recently by Yamanishi et al 8 to be 75.5%.…”

Solid-state NMR of quadrupolar halogen nuclei

“…Examples include using the temperature dependence of T 1 in NaCl and AgCl to calculate defect migration, the pressure and temperature dependence of d iso ( 35 Cl) in RbCl, and the effect of elastic strain on the chlorine CT line shape in NaCl, amongst others [39,[77][78][79][80][81].…”

Bond Fluctuation Model of Superionic Conductors: Concepts and Applications

“…Structure is surely an important factor that determines the fast ion transport within the solid, but it is not the only factor. Recent studies have revealed that superionic conduction is closely related to the bonding characteristics of the materials [3][4][5][6][7][8][9][10][11][12][13].…”