Mechanism for production of nonequilibrium rotational level populations of molecules in plasmas. I. Theoretical model
A mechanism is proposed for producing nonequilibrium distributions of molecules over the rotational levels of the electronic-vibrational ground state in low-pressure plasmas that involves purely rotational excitation of molecules by electron impact. Only intermolecular and electron--molecule collisions are included in the balance equation for excitation and deexcitation of the rotational levels in the electronic-vibrational ground state /sup 1/..sigma.., V = 0. An adiabatic approximation is used to relate the rate constants for arbitrary rotational transitions to the rate constants for rotational excitation from the rotational ground state. The deviation from adiabatic conditions in intermolecular collisions is taken into account by introducing an additional exponential factor. It is assumed that transitions between adjacent rotational levels are dominant. Some simple recurrence relations are derived and analyzed for the populations of the rotational levels. These relations link the form of the rotational distribution to the rates of elementary processes and to the plasma parameters, including the degree of ionization, the mean electron energy and the gas temperature.
- Research Organization:
- A. A. Zhdanov State University, Leningrad
- OSTI ID:
- 6141237
- Journal Information:
- Sov. Phys. - Tech. Phys. (Engl. Transl.); (United States), Journal Name: Sov. Phys. - Tech. Phys. (Engl. Transl.); (United States) Vol. 25:10; ISSN SPTPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700105* -- Fusion Energy-- Plasma Research-- Plasma Kinetics-Theoretical-- (-1987)
ADIABATIC APPROXIMATION
COLLISIONS
DISTRIBUTION
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
GROUND STATES
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
MOLECULES
PLASMA
PLASMA SIMULATION
ROTATIONAL STATES
SIMULATION