The Viscosities of Dilute Kr, Xe, and CO2 Revisited: New Experimental Reference Data at Temperatures from 295K to 690K

Previously reported, but also unpublished experimental data of our group for the viscosities of dilute krypton, xenon, and carbon dioxide, obtained in the range from 295K to a maximum of 690K using oscillating-disk viscometers, were re-evaluated and corrected or extrapolated to the limit of zero density (eta(0)). The combined standard uncertainty of the data is 0.1% at room temperature and 0.2% at higher temperatures. For krypton and carbon dioxide, our eta(0) data were compared with eta(0) values theoretically calculated using the kinetic theory and highly accurate ab initio potentials for the krypton atom pair and the CO2 molecule pair, but also with recent experimental eta(0) data from the literature. Our data for krypton differ up to 690K from the theoretical values by-0.10% to +0.28 %, whereas that of Lin et al. (Fluid Phase Equilib. 418: 198, 2016) show deviations of +(0.04 to 0.20)% at temperatures from 243K to 393 K, in each case proving that experiment and theory are in consistent agreement. The re-evaluated eta(0) data for xenon were compared with recent data from the literature and with calculated values resulting from the HFD-B potential for xenon via the corresponding-states principle to verify that they are reference values. For carbon dioxide, eta(0) values obtained from 26 re-evaluated isotherms and from eight isotherms of Schofer et al. (J Chem Thermodyn 89: 7, 2015) between 253 K and 473 K are mutually consistent with ab initio calculated and subsequently scaled viscosity values of Hellmann (Chem Phys Lett 613: 633, 2014). The isotherms of Schafer et al. are especially suitable for determining the initial density dependence of the viscosity. Concomitantly inferred reduced second viscosity virial coefficients were checked against two theoretical approaches of the Rainwater-Friend theory.