Measurements of He3—He4 and H2—D2 Gas Diffusion Coefficients

Abstract

The gas diffusion coefficient for ${\mathrm{He}}^3$-${\mathrm{He}}^4$ has been measured between 1.74 and 296°K, and for ${\mathrm{H}}_2$-${\mathrm{D}}_2$ between 13.9 and 296°K. The diffusion bridge used to make the measurements is described. The experimental results are compared with viscosity measurements, and with classical and quantum-mechanical calculations based on the Lennard-Jones 12-6 and on the modified Buckingham exp-6 intermolecular potential fields.