Near 25 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 [Bich et al. (2008)] and argon [Bich et al. (2007)] are probably much larger. We present new measurements of the viscosities of neon, argon, and krypton obtained at 25 C in a 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 The argon ratio agrees with a recent, unpublished calculation [JB Mehl, private communication (2012)] to within the combined uncertainty (measurement plus calculation) of 0.032 %. The neon ratio is smaller than the calculated value by 0.13 %.
Citation: Molecular Physics
Pub Type: Journals