Doppler spectral line broadening and the velocity distributions of excited atoms and molecules in nonequilibrium plasma

A set of methods for investigating the transnational motion of electron-excited particles in a nonequilibrium plasma based on spectral line profiles is developed using high resolution spectroscopy. These techniques are employed to investigate the nonequilibrium distribution functions of N2(C3Π) molecules and O(33P) atoms under excitation by metastable particles. A simple analytical model of the relaxation of the average energy of transnational motion is proposed that accurately describes experimental results. The 2+-system of N2 is used to demonstrate the possibility of identifying the particle excitation channels in nonequilibrium plasma from a comparison of the energy of the internal degrees of freedom and transnational motion. The kinetic Bolzmann equation with particle sources is solved numerically for the case of transnational relaxation of thermostat particles with a random mass ratio of the colliding partners in the solid sphere approximation