Noble gas viscosities at 25 °C

Abstract

Near 25 °C, ab initio calculations of the zero-density viscosity of helium gas η _He have an uncertainty of approximately 0.001%, which is 1/40th of the uncertainty of the best measurements. The uncertainties of the published calculations for neon and argon are probably much larger. This paper presents new measurements of the viscosities of neon, argon, and krypton at 25 °C made with a capillary viscometer that was calibrated with helium. The resulting viscosity ratios are η _Ne/η _He = 1.59836 ± 0.00037, η _Ar/η _He = 1.13763 ± 0.00030, and η _Kr/η _He = 1.27520 ± 0.00040. The argon ratio agrees with a recent, unpublished calculation to within the combined uncertainty (measurement plus calculation) of 0.032%. The neon ratio is smaller than the calculated value by 0.13%.

Keywords:

• gas viscosity
• helium
• neon
• argon
• krpyton
• capillary viscometer

Acknowledgements

We thank Mike Moldover for many useful conversations and suggestions, Jim Mehl for the unpublished calculated viscosity values for helium and argon, Wes Tew for information about neon isotopes, and Eckhard Vogel for pointing out the value of a new measurement of the viscosity of neon.