Lattice vibrational mode

To determine static properties of the SeO radical in KDP and DKDP, the temperature dependence of the hyperfine interaction between unpaired electron and Se (I = 1/2) nucleus was measured [53]. The hyperfine tensor component A, where the direction is along the c-axis, shows an isotope effect, because its value is higher in DKDP than in KDP. Furthermore, its value shows a jump at Tc for DKDP and a considerable temperature dependence in the PE phase of both crystals, approximated by the relation A (T) = A (0) - B coth(ro/T), where To 570 K for both crystals. It is interesting to note that A, similarly to the As NQR frequency and P isotropic chemical shift, should be constant in the PE phase if the two-state order-disorder mechanism of the corresponding tetrahedron holds. However, while the temperature dependencies of the As NQR frequency and P isotropic chemical shift in the PE phase were explained as originating from a six-state order-disorder mechanism [42] and additional displacive mechanism [46], respectively, here it was assumed that excitation of some extra lattice vibration mode with frequency Tq affects the hyperfine tensor components and causes the temperature dependence of A. ... 

However, the influence of the exchangeable cation on the framework vibrations has not been systematically investigated. From x-ray diffraction studies (2) on zeolites it is known that most of the exchangeable cations are firmly bound onto the negatively charged framework. Therefore these cations might have some influence on the lattice vibrational modes. 

The inelastic X-Ray scattering measurements [12] demonstrated a weak dispersion branch between 60 and 70 meV in the TA direction with E29 symmetry at the T point. The linewidth of this mode is about 20-j-28 meV along the TA direction, while along the TM direction it is below the experimental resolution. This points to the very strong electron-phonon interaction (EPI) for this particular lattice vibration mode. 

Klemens, P.G., Thermal Conductivity and Lattice Vibrational Modes, in Solid State Physics, F. Seitz and D. Thumbull, Editors. 1958, Academic Press, New York. p. 1-98. 

The specific heat (C) is the amount of energy required, per unit mass or per mole, to raise the temperature of a substance by one degree. This is the derivative of its internal energy dU/dT, and since magnetic levels make a contribution to this their separations can in principle be measured from C(T) measurements. However, the magnetic contribution to the specific heat must be disentangled from that of lattice vibrational modes. 

F. Denoyer, R. Comes, A. F. Garito and A. Y. Heeger, Phys. Rev. Lett. 35 (1975) 445, G. Shirane, Review paper at International Conference on Low Lying Lattice Vibrational Modes, San Juan, Puerto Rico, (1975) ... 

Add 10 mol % V2O5 shown that the Qxf value increased slightly with rising the sintering temperature. As temperature increased will caused the crystalline grain to be dense with each other. The microwave dielectric loss is mainly caused not only by the lattice vibration modes, but also by the pores, second phases, impurities or even the lattice defect. 

Lattice vibrations observed in toe Raman spectrum may also be used to characterise solvates. The spectmm of a chloroform solvate of griseofulvin and toe anhydrous form shows good correlation [57] indicating that toe stmcture of toe solvate is similar to that of toe parent molecule. The lattice vibration modes of toe solvate have shifted to lower frequency (Fig. 6.8) which can be... 

Kiefer B, Stixrude L (2001) Phase transition in MgSiOs perovskite. Nature submitted Kieffer SW (1979) Thermodyanamics and lattice vibrations of minerals, I mineral heat capacities and their relationship to simple lattice vibrational modes. Rev Geophys Space Phys 17 1-19 Kittel C (1996) Introduction to sohd state physics. Wiley, New York... 

The procedures for the symmetry classilieations of the lattice vibrational modes at additional symmetry points of the Brillouin zone can be modeled on the preceding ideas. The necessary character tables are given in the sources cited. 

SrTiOj (LB Number 1A-8). This crystal is cubic at room temperature and slightly tetragonal below 105 K. The phase transition at 105 K is caused by softening of the lattice vibration mode at the (1/2, 1/2, 1/2) Bril-... 

The Raman spectrum of the Ag anode after discharge in LiC104-based electrolyte is shown in Figure 14A. The Raman bands of the electrolyte are not observed in the spectrum. It has been reported that crystalline LijCOj has four molecular vibrational modes at 712(w), 748(w), 1090(s), 1460 cm (w) and five lattice vibrational modes at 96(s), 127(m), 156(s), 193(s), 272 cm (m) in the Raman spectrum. As seen in Figure 14A, the detection of the molecular vibrational bands of LijCOj demonstrates the existence of LijCOj on the Ag anode. However, the peaks corresponding to the lattice vibration are not observed, implying that the passivating layer on the Ag electrodes is probably amorphous, consistent with the HRTEM observations on, for example, the... 

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