Electronic quenching of OH(A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH(A–X) emission
By Peter Bruggeman, Felipe Iza, Peter Guns, D. Lauwers, Michael G. Kong, Y. A. Gonzalvo, C. Leys, D. Schram. 2010
148 citations recorded by the source corpus.
In this paper it is shown that electronic quenching of OH(A) by water prevents thermalization of the rotational population distribution of OH(A). This means that the observed ro-vibrational OH(A–X) emission band is (at least partially) an image of the formation process and is determined not only by the gas temperature. The formation of negative ions and clusters for larger water concentrations can contribute to the non-equilibrium. The above is demonstrated in RF excited atmospheric pressure glow discharges in He–water mixtures in a parallel metal plate reactor by optical emission spectroscopy. For this particular case a significant overpopulation of high rotational states appears around 1000 ppm H2O in He. The smallest temperature parameter of a non-Boltzmann (two-temperature) distribution fitted to the experimental spectrum of OH(A–X) gives a good representation of the gas temperature. Only the rotational states with the smallest rotational numbers (J ⩽ 7) are thermalized and representative for the gas temperature.
Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Radiology, Nuclear Medicine and Imaging
View Paper: https://www.semanticscholar.org/paper/657fcb261709a7cba3d6a46fe9c668f184fd0974
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In Radiology, Nuclear Medicine and Imaging
Citations in the corpus
- Ultrafast heating and oxygen dissociation in atmospheric pressure air by nanosecond repetitively pulsed discharges (2013, background): “This is an important question, because it is sometimes found that rotational temperatures of excited electronic states differ significantly from the gas temperature [50, 51].”