Helium virial coefficients—a comparison between new highly accurate theoretical and experimental data

Abstract

Critical tests of the accuracy of ab initio theoretical values of the helium virial coefficients have been made based on experiments with a new dielectric-constant gas thermometry (DCGT) setup established at PTB. As the main starting point, most accurate experimental results for the thermodynamic temperature and the dielectric polarizability of 3He and 4He have been deduced recently. This paper now concentrates on the results for the two- and three-particle interaction described by the second and third density virial coefficients of helium. A comparison between experimental DCGT results and new highly accurate theoretical ab initio results shows an impressive agreement. The experimental uncertainties have been estimated via Monte-Carlo simulations and are comparable to the uncertainty of the latest theory.