Calculation of the Viscosity of GaseousHe3andHe4at Low Temperatures

Abstract

The viscosity coefficients for gaseous ${\mathrm{He}}^3$ and ${\mathrm{He}}^4$ have been calculated to the second order approximation from 0°K to 40°K according to the quantum-mechanical theory of transport phenomena. Results are presented for two intermolecular potentials, the Lennard-Jones 12-6 (LJ1) and the exp-6 (MR5) functions. Contrary to expectation, LJ1 provides a better over-all fit to experimental data. A brief survey is given of the theory, previous calculations, and existing experimental data, with the conclusion that the low-temperature transport properties of the gaseous helium isotopes are not yet described with certainty by either experiment or theory.