Effective potential energies and transport cross sections for atom-molecule interactions of nitrogen and oxygen

The potential energy surfaces for H₂-N and N₂-N interactions are calculated by accurate ab initio methods and applied to determine transport data. The results confirm that an effective potential energy for accurately determining transport properties can be calculated using a single predetermined orientation. A simple method is developed to determine the dispersion coefficients of effective potential energies. Effective potential energies required for O₂-O collisions are determined. The H₂-N, N₂-N, O₂-H, and O₂-O collision integrals are calculated and tabulated for a broad range of temperatures. The theoretical values of the N₂-N and O₂-O diffusion coefficients compare well with measured data available at room temperature.