Noble gas viscosities at 25 °C

Near 25 degrees C, ab initio calculations of the zero-density viscosity of helium gas eta 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 degrees C made with a capillary viscometer that was calibrated with helium. The resulting viscosity ratios are eta Ne/eta He?=?1.59836 +/- 0.00037, eta Ar/eta He?=?1.13763 +/- 0.00030, and eta Kr/eta 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 The argon ratio agrees with a recent, unpublished calculation to within the combined uncertainty (measurement plus calculation) of 0.032%.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%.