Effect of Impurities on ESR Spectrum in Ge-S Glass

Temperature-dependent atomic B factor: an ab initio calculation

“…Our results are lower than these data and the discrepancy increases with temperature. The points deduced from the experimental data of Watanabe et al (1971) are instead closer to our theoretical values and have a similar temperature dependence. In the same figure we also report h B Bi calculated from a Debye model with D = 395 K the value derived from the LDA elastic constants which is quite close to the experimental one, D = 403 K. Also for Mg the h B Bi derived from the Debye model is smaller than the one derived from the ab initio lattice dynamics and hence even more distant from experiment.…”

“…opposite to the experimental anisotropy reported in the figure (Watanabe et al, 1971). In fact, experimental data for B B xx are quite close to the PBE theoretical values but the theoretical underestimation of the anisotropy leads to too small values of B B zz .…”

“…For instance, in h.c.p. metals a correlation has been found between the c/a ratio of the crystal parameters and the BF anisotropy (Watanabe et al, 1971).…”

“…7 we (Gao & Peng, 1999) of the BF derived from the experimental phonon density of states (orange) is also shown. The points are derived from the experimental data (Watanabe et al, 1971).…”

“…For instance Gopi Sirdeshmukh (1998) andShankar Narayana et al (2001) presented room-temperature meansquare atomic displacements for some hexagonal close-packed (h.c.p.) elements derived from powder diffraction experiments, while Watanabe et al (1971) used the single-crystal diffraction method to compute BFs for Cd, Mg and Mg 3 Cd at four different temperatures. Theoretical calculations on these systems are more rare although some rationalizations have been tried.…”