Kinetic theory of warm atoms: Non-Maxwellian velocity distributions and resulting Doppler-broadened emission-line profiles

Abstract

The Boltzmann equation is formulated and solved for the following spatially homogeneous and steady‐state system: Production of energetic [O(1S)] atoms by dissociative recombination of O2 +; removal of the [O(1S)] by emission; and thermalization by elastic and excitation exchange collisions with the abmient gas, asumed to be entirely O(3P). This system is an approximation to the physics of [O(1S)] in the nightime F2 region of the upper atmosphre, but the method can be applied to similar problems. The collision integrals are formulated in terms of scattering kernels. Emission line profiles are calculated from the velocity distriubtion for various values of the elastic and exchange collision frequencies. The accuracy of kinetic temperatures inferred from such line profiles is discussed.