We determined the zero-density viscosity and thermal conductivity of argon with an uncertainty of only 0.039 % in the temperature range 200 K to 400 K. Our results will improve: (1) the argon-argon interatomic potential, (2) calculated boundary-layer corrections for primary acoustic thermometry, and (3) calibrations of laminar flow meters as well as instruments for measuring transport properties. At 298.15 K, we determined the ratio = 1.13800 0.00018 from measurements of the flow rate of these gases through a quartz capillary of known dimensions and simultaneously measuring the pressures at the ends of the capillary. Between 200 K and 400 K, we used a two-capillary viscometer to determine = 1.21167 0.82034 exp(-T/123.78 K) with an uncertainty of 0.025 %. From , we computed using the values of calculated ab initio. Finally, we computed the thermal conductivity of argon from and values of the Prandtl number that we computed from argon-argon interatomic potentials.
Pub Type: Journals
ab initio calculations, argon, gases, helium, interatomic potential, Prandtl number, thermal conductivity, transport properties, viscosity