Debye model

About: Debye model is a research topic. Over the lifetime, 7462 publications have been published within this topic receiving 133987 citations.

P-V-T equation of state for ε-iron up to 80 GPa and 1900 K using the Kawai-type high pressure apparatus equipped with sintered diamond anvils

Abstract: [1] In order to determine the P-V-T equation of state of e-iron, in situ X-ray observations were carried out at pressures up to 80 GPa and temperatures up to 1900 K using the Kawai-type high pressure apparatus equipped with sintered diamond anvils which was interfaced with synchrotron radiation The present results indicate the unit cell volume at ambient conditionsV0 = 2215(5) A3, the isothermal bulk modulus KT0 = 202(7) GPa and its pressure derivative K′T0 = 45(2), the Debye temperature θ0 = 1173(62) K, Gruneisen parameter at ambient pressure γ0 = 32(2), and its logarithmic volume dependence q = 08(3) Furthermore, thermal expansion coefficient at ambient pressure was determined to be α0(K−1) = 37(2) × 10−5 + 72(6) × 10−8(T-300) and Anderson-Gruneisen parameterδT = 62(3) Using these parameters, we have estimated the density of e-iron at the inner core conditions to be ∼3% denser than the value inferred from seismological observation This result indicates that certain amount of light elements should be contained in the inner core as well as in the outer core but in definitely smaller amount

Molecular dynamics study of a dipolar fluid between charged plates. II

Abstract: Recent experiments and computer simulations of thin films have observed the segregation of nonpolar molecules into layers or sheets parallel to the confining walls. We discuss a molecular dynamics study of a thin film of Stockmayer molecules between Lennard‐Jones plates and find that, in the absence of an electric field, the dipoles are mainly oriented parallel to the plates in each layer. The component of the dipole autocorrelation function in this plane decays to zero more slowly than the component perpendicular to the walls. The polarization density profile, with an electric field perpendicular to the plates, is also studied, and is found to oscillate from layer to layer, with a magnitude that is in excess of what is predicted by the Debye theory of dielectric saturation by a factor nearly equal to the ratio of the local density to the average bulk density.

Lattice Vibrations in Alkali Halide Crystals. II. Potassium and Rubidium Halides; Cesium Fluoride

Abstract: Vibrational frequency distributions for the potassium and rubidium halides and for cesium fluoride have been evaluated on the basis of the Born lattice theory by the use of Blackman's numerical sampling method. Both room‐temperature and extrapolated 0°K parameters have been used in the calculation. Specific heats, the corresponding Debye characteristic temperatures, and the moments of the distributions have been obtained directly from the frequencies. Comparison is made with experimental data and with other theoretical work.

First-principles study of structural, elastic, electronic and thermodynamic properties of topological insulator Bi2Se3 under pressure

Abstract: The structural, elastic, electronic and thermodynamic properties of the rhombohedral topological insulator Bi2Se3 are investigated by the generalized gradient approximation (GGA) with the Wu–Cohen (WC) exchange-correlation functional. The calculated lattice constants agree well with the available experimental and other theoretical data. Our GGA calculations indicate that Bi2Se3 is a 3D topological insulator with a band gap of 0.287 eV, which are well consistent with the experimental value of 0.3 eV. The pressure dependence of the elastic constants Cij, bulk modulus B, shear modulus G, Young’s modulus E, and Poisson’s ratio σ of Bi2Se3 are also obtained successfully. The bulk modulus obtained from elastic constants is 53.5 GPa, which agrees well with the experimental value of 53 GPa. We also investigate the shear sound velocity VS, longitudinal sound velocity VL, and Debye temperature ΘE from our elastic constants, as well as the thermodynamic properties from quasi-harmonic Debye model. We obtain t...