The specific heat at constant volume,the entropy, the internal energy, and the free energy of liquid helium-4 between 1·2 and 2·9°K

Cryogenics ◽  
1961 ◽  
Vol 1 (4) ◽  
pp. 212-221 ◽  
Author(s):  
O.V. Lounasmaa
Keyword(s):  
Free Energy ◽  
Specific Heat ◽  
Liquid Helium ◽  
Internal Energy ◽  
Constant Volume ◽  
Helium 4

A First Principles Study of Thermal Properties of Yb-Pnictides (YbX, X= N, P and As) Compounds

2013 ◽  
Vol 665 ◽  
pp. 353-358
Author(s):  
Himadri R. Soni ◽  
Prafulla K. Jha
Keyword(s):  
Free Energy ◽  
Thermal Properties ◽  
Specific Heat ◽  
Internal Energy ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Constant Volume ◽  
Generalized Gradient ◽  
Lattice Specific Heat

Using first principles density functional theoretical calculations within the generalized gradient approximation (GGA), the present paper reports thermal properties such as constant volume lattice specific heat, Gibbs free energy, internal energy, and entropy of Yb-pnictides such as YbN, YbP and YbAs in its rocksalt phase. The variation of lattice specific heat with temperature obeys the classical Dulong-Petits law at high temperature while at low temperature it obeys Debye T3 law. The internal energy, entropy and free energy show a gradual variation with temperature. The specific heat at constant volume at lower temperature increases as going from N to P to As. *Corresponding author Email: [email protected], [email protected] Telephone: +91-278-2422650 Fax: +91-278-2426706

scholarly journals Anharmonic Contributions to the Vibratory Free Energy of a Lattice

1964 ◽  
Vol 17 (3) ◽  
pp. 269 ◽  
Author(s):  
P Lloyd
Keyword(s):  
Free Energy ◽  
Specific Heat ◽  
Constant Volume ◽  
Bethe Approximation ◽  
Rate Of Increase

The anharmonic contribution to the free energy of a lattice is evaluated by means of a Bethe approximation. The approximation is accurate to within 3% for the model valuated by Maradudin, Flinn, and Coldwell� Horsfall. The anharmonic contribution to the specific heat at constant volume of a model of sodium is evaluated.The specific heat is found to increase as the temperature rises but the rate of increase is lower than the observed value

scholarly journals Thermodynamic properties of CO 2 up to 3000 atmospheres between 25 and 150°C

1937 ◽  
Vol 160 (902) ◽  
pp. 376-384 ◽  
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Total Energy ◽  
Specific Heat ◽  
Interpolation Formula ◽  
Constant Volume ◽  
Present Communication ◽  
Different Temperatures

In previous papers (Michels and Michels 1935; Michels, Michels and Wouters 1935) the results of isotherm measurements on CO 2 and a method for interpolation of the pv values at intermediate temperatures and densities have been published. From the data obtained, the specific heat at constant volume C v , the free energy F , the total energy U , and the entropy S , have been calculated, and these results are given in the present communication. The values of F, U and S at N. T. P. have been taken as zero. The values of C v , F, S and U at a density of 1 Amagat unit ( ρ = 1) have first been calculated for different temperatures. To the values, so obtained, has been added the increase of these quantities by compression. The values of C v at ρ = 1 have been calculated, using the interpolation formula as given by Shilling and Partington (1928).

Ab initio study of thermodynamic properties of bulk zinc-blende CdS: Comparing the LDA and GGA

2018 ◽  
Vol 32 (20) ◽  
pp. 1850207 ◽  
Author(s):  
Fatemeh Badieian Baghsiyahi ◽  
Arsalan Akhtar ◽  
Mahboubeh Yeganeh
Keyword(s):  
Free Energy ◽  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Internal Energy ◽  
Density Functional ◽  
Helmholtz Free Energy ◽  
Constant Volume ◽  
Grüneisen Parameter ◽  
Zinc Blende

In the present study, we have investigated the phonon and thermodynamic properties of bulk zinc-blende CdS by first-principle calculations within the density functional theory (DFT) and the density functional perturbation theory (DFPT) method using the quasi harmonic approximation (QHA). We calculated the phonon dispersion at several high symmetry directions, density of phonon state, temperature dependence feature of Helmholtz free energy (F), internal energy, bulk modulus, constant-volume specific heat, entropy, coefficient of the volume thermal expansion and Grüneisen parameter estimated with the local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange-correlation potential and compared them with each other. For internal energy, Helmholtz free energy, constant volume heat capacity and phonon entropy the LDA and GGA results are very similar. But, the LDA gives lattice constants that are smaller than GGA while phonon frequencies, bulk modulus and cohesive energies are larger. On the other hand, the results obtained through the GGA approximation for the coefficient of the volume thermal expansion and Grüneisen parameter are larger than those obtained from LDA.

THERMODYNAMIC AND MAGNETIC PROPERTIES OF THE ARCHIMEDEAN LATTICES

2005 ◽  
Vol 19 (28) ◽  
pp. 4259-4267 ◽  
Author(s):  
Q. L. ZHANG
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Magnetic Properties ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Internal Energy ◽  
Type 3 ◽  
Ising Spins ◽  
Frustration Effects

We numerically study the thermodynamic properties of two Archimedean lattices1 with Ising spins using Wang–Landau algorithm of the Monte Carlo simulation. The two Archimedean lattices are of the type (3, 122) and Kagomé, for which we are particularly interested in the frustration effects. The internal energy, specific heat, free energy, entropy, magnetization and spin susceptibility are calculated.

The Thermodynamic properties of solid and fluid helium-3 and helium-4 above 3 °K at high densities

1964 ◽  
Vol 257 (1076) ◽  
pp. 1-29 ◽  
Keyword(s):  
Melting Point ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Fluid Phase ◽  
Constant Volume ◽  
Lattice Vibrations ◽  
Harmonic Model ◽  
Helium 4 ◽  
Helium 3 ◽  
Solid 3He

Measurements have been made of the specific heat at constant volume of solid 3He from 3 K up to the melting point at a number of different densities corresponding to pressures up to 2000 atm. The measurements have been extended through the melting region at constant volume up to 29 °K in the fluid phase. For comparison similar measurements have been made on 4He at four different densities. By combining these data with the p- V- T data of Mills & Grilly (1955) and Grilly & Mills (1959) the complete thermodynamic properties of the solids have been derived in the relevant pressureand temperature range. The results can be understood semi-quantitatively in terms of the zeropointenergy of the solids and a quasi-harmonic model of the lattice vibrations. A brief discussion of the specific heat of the fluid phase is also given.

The thermodynamic properties of fluid helium

1960 ◽  
Vol 252 (1013) ◽  
pp. 357-395 ◽  
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Internal Energy ◽  
Thermodynamic Functions ◽  
Single Phase ◽  
Constant Pressure ◽  
Pressure Coefficient ◽  
Differential Method ◽  
Constant Volume ◽  
Gibbs Function

Measurements have been made from which all the thermodynamic properties of fluid helium can be calculated in the temperature range from 3 to 20 °K and up to 100 atm pressure. The quantities measured were: (i) the specific heat at constant volume as a function of temperature and density, (ii) the pressure coefficient at constant volume ( also as a function of temperature and density, (iii) the pressure as a function of temperature at constant volume (isochores) for a range of densities. A particular feature of the experiments is that the important derivative ( )v, from which the changes of entropy and internal energy with volume at constant temperature are calculated, was measured directly by a differential method. Starting from the known entropy and internal energy of the liquid near its normal boiling point, these two quantities were calculated for all single phase states within the experimental range. From these, and using the equation of state data, the enthalpy, free energy, Gibbs function, and the specific heat at constant pressure have been deduced. The thermodynamic functions, together with some useful state properties, are tabulated as functions of temperature and either volume or pressure as relevant. The choice of the measured quantities was such that all the thermodynamic functions except the specific heat at constant pressure were obtained by integration of the experimental data; these functions therefore have the same accuracy as the measured quantities, about 1 %.

scholarly journals Theory of Heat Capacity of Liquid Helium-4 for Temperatures above the Critical Point

2012 ◽  
Vol 57 (12) ◽  
pp. 1214
Author(s):  
I.O. Vakarchuk ◽  
V.S. Pastukhov ◽  
R.O. Prytula
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Critical Point ◽  
Effective Mass ◽  
Liquid Helium ◽  
Internal Energy ◽  
Simple Calculation ◽  
Entire Temperature Range ◽  
Temperature Range ◽  
Helium 4

We analyze numerically the behavior of the heat capacity of liquid 4He for the entire temperature range with the corresponding formula for the internal energy obtained in Ref. [I.O. Vakarchuk, R.O. Prytula, A.A. Rovenchak, J. Phys. Stud. 11, 259 (2007)] combined with a simple calculation of the effective mass of interacting Bose particles. The results agree quite well with experimental data.

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