Unexpected rotational distribution of the ground electronic state OH(X-2 pi) generated by plasma at the interface with liquid water
| Authors | |
|---|---|
| Year of publication | 2018 |
| Type | Article in Periodical |
| Magazine / Source | PLASMA SOURCES SCIENCE & TECHNOLOGY |
| MU Faculty or unit | |
| Citation | |
| Web | http://dx.doi.org/10.1088/1361-6595/aad0e3 |
| Doi | http://dx.doi.org/10.1088/1361-6595/aad0e3 |
| Keywords | hydroxyl radical; laser-induced fluorescence; rotational distribution; temperature quasi-Boltzmann; streamer; liquid water interface |
| Description | An unexpected rotational distribution of the ground electronic state OH(X-2 pi) was observed by laser-induced fluorescence in a surface barrier discharge in contact with a liquid water interface. Analysis assuming a Boltzmann distribution yielded an unrealistically high rotational temperature above 600 K in the post-discharge phase. This is interpreted as a quasi-Boltzmann rotational distribution that is not in equilibrium with the translational temperature of the background gas. While the peculiarities of rotational distribution of excited OH(A(2) Sigma(+)) are known, the presented results show that even the ground electronic state OH(X-2 pi) does not always have to be a reliable indicator for spectroscopic thermometry in plasmas containing water. A series of similar observations challenges the usual approach in kinetic models, when the rotational distribution is assumed to follow the Boltzmann function with the temperature of surrounding gas. |
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