Topic
Debye model
About: Debye model is a research topic. Over the lifetime, 7462 publications have been published within this topic receiving 133987 citations.
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TL;DR: The band motion (tunneling) of small polarons in thermally activated energy levels of molecules is postulated to be the conduction mechanism is some organic and biological semiconductors and the compensation law is derived from this model.
Abstract: The band motion (tunneling) of small polarons in thermally activated energy levels of molecules is postulated to be the conduction mechanism is some organic and biological semiconductors. The compensation law is derived from this model. The characteristic temperature is shown to be related to the Debye temperature.
41 citations
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TL;DR: The heat capacity of the dichalcogenide: tungsten ditelluride, WTe2, was measured over the temperature range 5.5 to 7.5 in this article.
41 citations
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TL;DR: In this article, the widths and shapes of the three groups of absorption lines in ruby are measured in the 77-500°K temperature range and the observed asymmetric shape of the B 3 and R 3' lines are due to the energy dependent one-phonon relaxation rate.
Abstract: Widths and shapes of the three groups of absorption lines in ruby are measured in the 77–500°K temperature range. Temperature-dependent linewidths are successfully interpreted in terms of the direct and Raman relaxations. The observed asymmetric shapes of the B 3 and R 3' lines are shown to be due to the energy dependent one-phonon relaxation rate. Non-empirical calculations are made on transition probabilities and stress-induced changes in level splittings of the t 2 3 2 E 1 , 2 T 1 and 2 T 2 states. Orbit-lattice parameters are evaluated using point charge model with Watson's Hartree-Fock function for a free Cr 3+ ion. Mixing of all the doublet states with d 3 electron configuration is taken into account. Agreement between calculation and experiment is surprisingly good. Cubic symmetry approximation and point charge model are shown to be very good. Some slight discrepancies between the calculated rates and experiment are explained by the deviation of the Debye model from a more realistic phonon spectrum...
41 citations
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TL;DR: In this paper, high-resolution 4f core-level spectra of the Ta(110) surface region have been obtained at 80 and 300 K with 70 and 100 eV synchrotron radiation.
Abstract: High-resolution 4f core-level spectra of the Ta(110) surface region have been obtained at 80 and 300 K with 70- and 100-eV synchrotron radiation. The data show that the subsurface core-level binding-energy shift (compared to deeper-lying atoms) for a close-packed bcc(110) surface can be substantial: 65\ifmmode\pm\else\textpm\fi{}15 meV for the first underlayer atoms of Ta(110). The surface core-level shift is 360\ifmmode\pm\else\textpm\fi{}12 meV at 80 K and decreases by 13\ifmmode\pm\else\textpm\fi{}2 meV at 300 K. Final-state screening in both the bulk and surface layers is well described by a constant singularity index of 0.133\ifmmode\pm\else\textpm\fi{}0.012. An enhanced phonon broadening at the surface corresponds to a reduced perpendicular Debye temperature for the surface atoms of 128\ifmmode\pm\else\textpm\fi{}18 K compared to the bulk Debye temperature of 225 K.
41 citations
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TL;DR: In this paper, the role of MoO3 content on the deformation of lead-molybdenum lead phosphate glasses was investigated using sound velocity measurements at 4 MHz.
Abstract: Molybdenum lead phosphate glasses doped with La2O3 of the system xMoO3–5La2O3–50P2O5–(45−x)PbO, with 0≤x≤25 mol%, have been synthesized and studied by FTIR, ultrasonic and differential scanning calorimetry (DSC) in order to investigate the role of MoO3 content on their atomic structure. The constants of elasticity and Debye temperatures of the glasses have been investigated using sound velocity measurements at 4 MHz. According to the IR analysis, the vibrations of the phosphate structural units are shifted towards higher wavenumbers associated with the formation of bridging oxygens. The change in density with MoO3 content reveals that the molybdate units are less dense than the lead units. The observed compositional dependence of the constants of elasticity is interpreted in terms of the effect of MoO3 on the different phosphate bonds. It is assumed that MoO3 plays the role of a former by increasing the ultrasonic velocity and the constants of elasticity of the phosphate glasses.
41 citations