Solubility of Hydrogen and Deuterium in Liquid Argon

Abstract

The solubility of hydrogen and deuterium in liquid argon at pressures from 10 to 100 atm is reported. Solubility isotherms have been measured between 87° and 140°K for hydrogen and between 87° and 120°K for deuterium. The dependence of Henry's constant on temperature, pressure, and concentration, the heats of solution, the partial molar volume of hydrogen in liquid argon, and the second virial coefficients of hydrogen and deuterium in the liquid solution are reported. The increase in the solubility of deuterium over hydrogen is 21.3%, 20.2%, and 18.5%, respectively, at 87, 100, and 120°K. This isotope effect is discussed as a quantum correction to the free volume. Comparison between theory and experiment indicates that the LJD free volume is too large by approximately a factor of five.