ANHARMONIC CONTRIBUTIONS TO THE BULK MODULUS AND CHARACTERISTIC TEMPERATURES OF NEON AND ARGON AT T = 0 °K

1967 ◽  
Vol 45 (9) ◽  
pp. 2995-2997 ◽  
Author(s):  
J. S. Brown ◽  
G. K. Horton
Keyword(s):  
Bulk Modulus ◽  
Excellent Agreement ◽  
Characteristic Temperature ◽  
Experimental Results ◽  
Debye Characteristic Temperature ◽  
Characteristic Temperatures ◽  
Lennard Jones ◽  
Anharmonic Potential ◽  
Potential Parameters

Anharmonic contributions to the bulk moduli of Ne and Ar are calculated for Lennard-Jones (m–6) potentials and compared with the experimental results at T = 0 °K. We consider direct anharmonic contributions to the bulk moduli and the anharmonic contributions via the use of Brown's (1966) anharmonic potential parameters. Excellent agreement is found with the experimental results of Peterson, Batchelder, and Simmons (1966) and Batchelder, Losee, and Simmons (1967).We also study the effect of the anharmonic parameters on the Debye characteristic temperature obtained from Cν. Improved agreement with the experimental results is found.

Note on the Characteristic Temperatures of Sphalerite-Structure Semiconductors

1972 ◽  
Vol 50 (11) ◽  
pp. 1220-1221 ◽  
Author(s):  
M. D. Aggarwal ◽  
V. Raju ◽  
J. K. D. Verma
Keyword(s):  
Characteristic Temperature ◽  
Sphalerite Structure ◽  
Debye Characteristic Temperature ◽  
Characteristic Temperatures

The characteristic temperatures of III–V sphalerite semiconductors have been calculated by using the Reeber–McLachlan relation. These values do not follow the same trend as obtained for II–VI solids. However, the agreement with the Debye characteristic temperature is fair.

Debye Characteristic Temperatures of Cubic Metals

1972 ◽  
Vol 50 (21) ◽  
pp. 2712-2714 ◽  
Author(s):  
B. S. Semwal ◽  
P. K. Sharma
Keyword(s):  
Shear Modulus ◽  
Numerical Integration ◽  
Elastic Constants ◽  
Characteristic Temperature ◽  
Debye Characteristic Temperature ◽  
Cubic Metals ◽  
Characteristic Temperatures ◽  
Metallic Element ◽  
Elastic Data ◽  
Direct Numerical Integration

The validity of Hill's formulas for the shear modulus of a polycrystalline cubic solid is examined by calculating the Debye characteristic temperature at 0 °K for a number of cubic metals using the measured elastic constants. The results are compared with calorimetric values and the numbers deduced from direct numerical integration of elastic data. Various methods give nearly similar results if the anisotropy of the metallic element is not excessively large.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

The crystal dynamics of cuprous halides

1982 ◽  
Vol 60 (11) ◽  
pp. 1589-1594 ◽  
Author(s):  
Manvir S. Kushwaha
Keyword(s):  
Phonon Dispersion ◽  
Characteristic Temperature ◽  
Force Model ◽  
Phonon Dispersion Curves ◽  
Debye Characteristic Temperature ◽  
Zinc Blende ◽  
Crystal Dynamics ◽  
Bond Bending ◽  
Dynamical Description ◽  
Good Agreement

The lattice dynamics of cuprous halides have been thoroughly investigated by means of an 8-parameter bond-bending force model (BBFM), recently developed and applied successfully to study phonons in various II–VI and III–V compound semiconductors having zinc-blende (ZB) structure. The application of BBFM is made to calculate the phonon dispersion relations, phonon density of states, and temperature variation of the Debye characteristic temperature [Formula: see text] of CuCl, CuBr, and CuI. The room-temperature neutron scattering measurements for phonon dispersion curves along three principal symmetry directions and calorimetric experimental data for the Debye characteristic temperature have been used to check the validity of BBFM for the three crystals. The overall good agreement between theoretical and experimental results supports its use as an appropriate model for the dynamical description of ZB crystals.

Ab Initio Investigation of Structural and Electronic Properties of ErPb3 in AB3 Structure

2016 ◽  
Vol 28 ◽  
pp. 39-42 ◽  
Author(s):  
Shubha Dubey ◽  
Gitanjali Pagare ◽  
Ekta Jain ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Total Energy ◽  
Electronic Properties ◽  
Density Of States ◽  
Experimental Results ◽  
Energy Calculation ◽  
Present Calculation ◽  
Full Potential ◽  
Local Spin Density Approximation ◽  
Calculated Density

The structural properties and electronic properties of the intermetallic compound ErPb3 which crystallize in AuCu3 type structure (AB3) are studied by means of first principles total energy calculation using full potential linearized plane wave method (FP-LAPW) within the generalized gradient approximation of Perdew, Burke and Ernzrhof (PBE) and local spin density approximation (LSDA) for the exchange correlation functional and including spin magnetic calculation. The total energy is computed as a function of volume and fitted to the Birch-Murnaghan equation of state. The ground state properties of this compound such as equilibrium lattice parameter (a0), bulk modulus (B), and its pressure derivative (B’) are calculated and compared with the available experimental results. We find good agreement with the other theoretical and experimental results. For the compounds, the values of lattice constants obtained by PBE-GGA overestimates and by LSDA underestimates the available experimental values for the same, which verifies the reliability of the present calculation. The value obtained for the bulk modulus is 50.63 GPa. The analysis of electronic properties is achieved by the calculation of the band structures and the density of states in both the spin up and spin down modes, which show a metallic character of ErPB3 due to zero band gap. The values of calculated density of states are found to be 0.36 eV/states and 11.46 eV/states in spin-up and spin-down mode respectively. The calculated magnetic moment (μm) of ErPb3 is 2.06.

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