Third density and acoustic virial coefficients of helium isotopologues from ab initio calculations

Abstract

Improved two-body and three-body potentials for helium have been used to calculate from first principles the third density and acoustic virial coefficients for both ${}^4$He and ${}^3$He. For the third density virial coefficient $C(T)$, uncertainties have been reduced by a factor of 4--5 compared to the previous state of the art; the accuracy of first-principles $C(T)$ now exceeds that of the best experiments by more than two orders of magnitude. The range of calculations has been extended to temperatures as low as 0.5~K. For the third acoustic virial coefficient ${\gamma }_a(T)$, we applied the Schlessinger Point Method, which can calculate ${\gamma }_a$ and its uncertainty based on the $C(T)$ data, overcoming some limitations of direct path-integral calculation. The resulting ${\gamma }_a$ are calculated at temperatures down to 0.5~K; they are consistent with available experimental data but have much smaller uncertainties. The first-principles data presented here will enable improvement of primary temperature and pressure metrology based on gas properties.

21 pages, 14 figures

References in corpus (4)

• Second virial coefficients for helium-4 and helium-3 from accurate relativistic interaction potential
• Fresh extraction of the proton charge radius from electron scattering
• Ab initio Calculation of Fluid Properties for Precision Metrology
• Path-integral calculation of the fourth virial coefficient of helium isotopes

Cited by in corpus (4)

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• Path-integral Monte Carlo simulations of solid parahydrogen using two-body, three-body, and four-body ab initio interaction potential energy surfaces
• Third and fourth density and acoustic virial coefficients of neon from first-principles calculations