Solid helium. II. Pressure and compressibility calculated by a lowest-order constrained-variation method

1987 ◽  
Vol 35 (10) ◽  
pp. 4713-4718 ◽  
Author(s):  
Otto Svorstl ◽  
Erlend stgaard
Keyword(s):  
Solid Helium ◽  
Variation Method ◽  
Helium Ii ◽  
Constrained Variation

Spin-polarized hydrogen, deuterium, and tritium: I. Ground-state energy calculated by a lowest order constrained-variation method

1989 ◽  
Vol 67 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Magne Haugen ◽  
Erlend Østgaard
Keyword(s):  
Binding Energy ◽  
Molar Volume ◽  
Ground State ◽  
Particle Density ◽  
Variation Method ◽  
Ground State Binding Energy ◽  
Spin Polarized ◽  
Hydrogen Deuterium ◽  
Constrained Variation ◽  
Theoretical Results

The ground-state energy of spin-polarized hydrogen, deuterium, and tritium is calculated by means of a modified variational lowest order constrained-variation method, and the calculations are done for five different two-body potentials. Spin-polarized H↓ is not self-bound according to our theoretical results for the ground-state binding energy. For spin-polarized D↓, however, we obtain theoretical results for the ground-state binding energy per particle from −0.42 K at an equilibrium particle density of 0.25 σ−3 or a molar volume of 121 cm3/mol to + 0.32 K at an equilibrium particle density of 0.21 σ−3 or a molar volume of 142 cm3/mol, where σ = 3.69 Å (1 Å = 10−10 m). It is, therefore, not clear whether spin-polarized deuterium should be self-bound or not. For spin-polarized T↓, we obtain theoretical results for the ground-state binding energy per particle from −4.73 K at an equilibrium particle density of 0.41 σ−3 or a molar volume of 74 cm3/mol to −1.21 K at an equilibrium particle density of 0.28 σ−3 or a molar volume of 109 cm3/mol.

The thermal conductivity of solid helium

1952 ◽  
Vol 214 (1119) ◽  
pp. 546-563 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Single Crystals ◽  
Liquid Helium ◽  
Solid Helium ◽  
Boundary Scattering ◽  
Conductivity Measurements ◽  
Helium Ii ◽  
Characteristic Temperatures ◽  
Thermal Conductivities

The thermal conductivities of crystals of solid helium at densities between 0⋅194 and 0⋅218 g/cm 3 have been measured at liquid-helium temperatures. In order to interpret the results, the specific heat of solid helium at these densities has been measured from 0⋅6 to 1⋅4° K. The range of densities employed is sufficient to allow the observation of Debye characteristic temperatures varying by 40 %, and of thermal conductivities varying by factors of over 10. It is shown that the conductivity measurements are in accord with the ‘umklapp’ type of thermal resistance derived by Peierls (1929, 1935). Further work was restricted by the difficulty of obtaining good single crystals in narrow tubes, but measurements of the conductivity at one density were obtained down to 0⋅3° K. In this region the conductivity is limited by boundary scattering and is higher than that observed by other authors for liquid helium II at similar temperatures.

Spin-polarized hydrogen, deuterium, and tritium: II. Pressure and compressibility calculated by a lowest order constrained-variation method

1989 ◽  
Vol 67 (7) ◽  
pp. 649-656 ◽  
Author(s):  
Magne Haugen ◽  
Erlend Østgaard
Keyword(s):  
Molar Volume ◽  
Ground State ◽  
Particle Density ◽  
Variation Method ◽  
Density Region ◽  
Spin Polarized ◽  
Hydrogen Deuterium ◽  
Constrained Variation ◽  
Ground State Energies ◽  
Theoretical Results

The pressure and the compressibility of spin-polarized H↓, D↓, and T↓ are obtained from ground-state energies calculated by means of a modified variational lowest order constrained-variation method. The pressure and the compressibility are calculated or estimated from the dependence of the ground-state energy on density or molar volume, generally in a density region from 0 to 1.5σ−3 corresponding to a molar volume of more than 20 cm3/mol, where σ = 3.69 Å (1Å = 10−10 m); the calculations are done for five different two-body potentials. Theoretical results for the pressure are 54.1–57.9 atm for spin-polarized H↓ 18.4–23.4 atm for spin-plolarized D↓, and 5.6–12.9 atm for spin-polarized T↓ at a particle density of 0.50σ−3 or a molar volume of 60 cm3/mol (1 atm = 101 kPa). Theoretical results for the compressibility are 51 × 10−4 −54 × 10−4 atm−1 for spin-polarized H↓, 108 × 10−4 −120 × 10−4 atm−1 for spin-polarized D↓, and 162 × 10−4 −224 × 10−4 atm−1 for spin-polarized T↓ at a particle density of 0.50σ−3 for a molar volume of 60 cm3/mol. The relative agreement between results for different potentials is somewhat better for higher densities.

Solid helium. II. Exchange energy in solid3He

1972 ◽  
Vol 7 (5-6) ◽  
pp. 471-489 ◽  
Author(s):  
E. �stgaard
Keyword(s):  
Solid Helium ◽  
Exchange Energy ◽  
Helium Ii

Kapitza resistance between liquid and solid helium. II. Experiments

1982 ◽  
Vol 48 (5-6) ◽  
pp. 463-475 ◽  
Author(s):  
T. E. Huber ◽  
Humphrey J. Maris
Keyword(s):  
Solid Helium ◽  
Kapitza Resistance ◽  
Helium Ii
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