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

Abstract

The potential energy surfaces for ${\mathrm{H}}_{2}\ensuremath{-}\mathrm{N}$ and ${\mathrm{N}}_{2}\ensuremath{-}\mathrm{N}$ 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 ${\mathrm{O}}_{2}\ensuremath{-}\mathrm{O}$ collisions are determined. The ${\mathrm{H}}_{2}\ensuremath{-}\mathrm{N},$ ${\mathrm{N}}_{2}\ensuremath{-}\mathrm{N},$ ${\mathrm{O}}_{2}\ensuremath{-}\mathrm{H},$ and ${\mathrm{O}}_{2}\ensuremath{-}\mathrm{O}$ collision integrals are calculated and tabulated for a broad range of temperatures. The theoretical values of the ${\mathrm{N}}_{2}\ensuremath{-}\mathrm{N}$ and ${\mathrm{O}}_{2}\ensuremath{-}\mathrm{O}$ diffusion coefficients compare well with measured data available at room temperature.