Accession Number : ADA307174

Title :   Spectroscopic Measurements of Water Vapor Plasmas at High Resolution - The Optical Transition Probabilities for OH(A -X II).

Descriptive Note : Contract rept.,

Corporate Author : GREYRAD CORP PRINCETON NJ

Personal Author(s) : Klein, Lothar

PDF Url : ADA307174

Report Date : AUG 1972

Pagination or Media Count : 152

Abstract : Emission and absorption spectra of water vapor plasmas generated in a wall stabilized arc at atmospheric pressure and 4 A current, and at 0.03 atm and 15 to 50 A, were measured at high spatial and spectral resolution. The gas temperature was determined from the shape of Doppler broadened rotational lines of OH since the measured resolving power of the spectrometer was 400,000. The observed nonequilibrium population distributions over the energy levels of atoms are interpreted in terms of a theoretical state model for diffusion controlled arc plasmas. Excellent correlation is achieved between the measured and the predicted occupation of the hydrogen energy levels. It is shown that the population distribution over the non predissociating rotational vibrational levels of the A 2Sigma state of OH is close to an equilibrium distribution at the gas temperature, although the total density of this state is much higher than its equilibrium density. The reduced intensities of the rotational lines originating in these levels yielded Boltzmann plots that were strictly linear, but the slope did not correspond to the measured gas temperature. This is attributed to an exponential dependence of the transition moment on the rotational energy term. Appropriate correction factors were calculated and compared with theoretical predictions.

Descriptors :   *PLASMAS(PHYSICS), *EMISSION SPECTRA, *ABSORPTION SPECTRA, *WATER VAPOR, THERMAL PROPERTIES, SPATIAL DISTRIBUTION, OPTICAL PROPERTIES, PREDICTIONS, MOLECULAR VIBRATION, SHAPE, MOMENTS, EQUILIBRIUM(GENERAL), HIGH RESOLUTION, HYDROGEN, ULTRAVIOLET SPECTROSCOPY, MOLECULAR ROTATION, NONEQUILIBRIUM FLOW, BAROMETRIC PRESSURE, ENERGY LEVELS, PLOTTING, BOLTZMANN EQUATION, SPECTROMETERS, HYDROXYL RADICALS, CORRECTIONS, SPECTRAL LINES.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE