Search

The thermodynamic properties and distribution functions of highly compressed molecular hydrogen are investigated in a nonempirical atom-atom approximation. Quantum corrections are introduced on the basis of the Feynman variational approach. The pressure, energy, compressibility, thermal expansion, heat capacity, and sound velocity are calculated by the Monte Carlo method at temperatures of 200-500 K and pressures up to 5 GPa. The results are compared with the available experimental data. It is shown that effects due to incompressibility of the molecules and quantum effects must be taken into account in calculating the contributions to the thermodynamic functions from inter- and intramolecular forces. The behavior of the properties of fluid hydrogen near the line of crystallization outside the investigated region is predicted, and an estimate is made for the jump in volume upon crystallization of hydrogen at T=300 K. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]