The thermodynamics of hydrogen and hydrogen-methane mixtures

Abstract

Thermodynamic perturbation theory is applied to the calculation of the thermodynamics of hydrogen and hydrogen-X mixtures. Quantum corrections to O(ℏ²) are included, and perturbation methods are used to estimate the mean squared torque and mean squared force on a molecule. These methods are tested by comparison with molecular dynamics results for the hydrogen model used in the theory. The theoretical calculations show that the method is satisfactory for temperatures above 80–130 K, the precise temperature depending on the density and property considered. Comparisons are made with experimental data for pure hydrogen and for hydrogen-methane mixtures.