2ND-ORDER CORRECTIONS FOR TRANSPORT-PROPERTIES OF PURE DIATOMIC GASES

Second-order kinetic theory expressions involving either internal angu lar momentum or translational and rotational energies have been invest igated for two potential energy surfaces for N-2 at temperatures betwe en 77 and 1000 K. The largest correction is for the volume viscosity, where it is about 15% at 300 K and 20% at 600 K. For the thermal condu ctivity the angular-momentum related correction is approximately 1% an d varies weakly with temperature, while the rotational and translation al-energy-related correction increases with temperature, reaching appr oximately 1% at 1000 K. For the shear viscosity both corrections are n o more than 0.5%. The Mason-Monchick approximation provides useful est imates of the energy-related corrections for the thermal conductivity and shear viscosity. Results calculated using the ab initio potential energy surface of Van der Avoird ct al, agree better with experiment t han those using the site-site potential of MacRury et al. for the shea r viscosity and the thermal conductivity over a wide temperature range . However, for the volume viscosity the site-site potential yields res ults in somewhat better agreement with the observations.