Laser-Plasma Spectroscopy of Hydroxyl with Applications

Molecules. 2020 Feb 22;25(4):988. doi: 10.3390/molecules25040988.

Abstract

This article discusses laser-induced laboratory-air plasma measurements and analysis of hydroxyl (OH) ultraviolet spectra. The computations of the OH spectra utilize line strength data that were developed previously and that are now communicated for the first time. The line strengths have been utilized extensively in interpretation of recorded molecular emission spectra and have been well-tested in laser-induced fluorescence applications for the purpose of temperature inferences from recorded data. Moreover, new experiments with Q-switched laser pulses illustrate occurrence of molecular recombination spectra for time delays of the order of several dozen of microseconds after plasma initiation. The OH signals occur due to the natural humidity in laboratory air. Centrifugal stretching of the Franck-Condon factors and r-centroids are included in the process of determining the line strengths that are communicated as a Supplementary File. Laser spectroscopy applications of detailed OH computations include laser-induced plasma and combustion analyses, to name but two applications. This work also includes literature references that address various diagnosis applications.

Keywords: astrophysical spectroscopy; combustion analysis; diatomic molecules; laser spectroscopy; laser-induced breakdown spectroscopy; molecular excitation temperature; molecular spectra; optical emission spectroscopy; plasma diagnostics; plasma spectroscopy.

MeSH terms

  • Gases / chemistry*
  • Hydroxyl Radical / chemistry*
  • Lasers
  • Light
  • Spectrum Analysis*
  • Temperature

Substances

  • Gases
  • Hydroxyl Radical