Collision integrals for the interaction of the ions of nitrogen and oxygen in a plasma at high temperatures and pressures

The corrections to the transport cross sections and collision integrals for Coulomb interactions arising from the application of realistic interaction energies of the ions of nitrogen and oxygen have been investigated. Accurate potential energy curves from an ab initio electronic structure calculation and a semiclassical description of the scattering are used to determine the difference between the cross sections for the real interaction forces and a Coulomb force for large values of the Debye shielding parameter. Graphs of the correction to the diffusion and viscosity collision integrals are presented for temperatures from about 10 000 K to 150 000 K. This correction can be combined with tabulations of the collision integrals for shielded Coulomb potentials to determine the contribution of N+–N+, N+–O+, and O+–O+ interactions to the transport properties of high-temperature air. Analytical forms have been fitted to the calculated results to assist this application.