Laser-Plasma Spectroscopy of Hydroxyl with Applications

Abstract

This article discusses laser-induced laboratory-air plasma measurements and analysis of hydroxyl (OH) ultraviolet spectra. 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 computation of the emission spectra utilizes line strength data that are communicated as a supplementary file. Applications of detailed OH computations include laser-induced plasma and combustion analyses, to name but two applications.

Fundamentals of Diatomic Molecular Spectroscopy

“…Various reported studies of plasma spectra, including astrophysics plasma, and of molecular laser-induced breakdown spectroscopy [38][39][40][41] illustrate nice comparisons of recorded and of computed diatomic spectra.…”

“…The published program package [38] also includes a worked high-temperature cyanide example, the Boltzmann equilibrium spectrum program (BESP) for computation of equilibrium spectra and the Nelder-Mead temperature (NMT) routine that utilizes a non-linear fitting algorithm. The OH line strength data have been made available recently [39].…”

Introduction to applications of diatomic spectroscopy

“…The published program package [42] also includes a worked high-temperature cyanide example, the Boltzmann equilibrium spectrum program (BESP) for computation of equilibrium spectra, and the Nelder-Mead temperature (NMT) routine that utilizes a non-linear fitting algorithm. The OH line strength data have been made available recently [43].…”

Diatomic Line Strengths for Fitting Selected Molecular Transitions of AlO, C₂, CN, OH, N₂⁺, NO, and TiO, Spectra

“…In several cases, molecular spectra may not be of primary interest in elemental analysis with LIBS using nanosecond laser pulses, but molecular spectra are readily observed with femtosecond laser-plasma excitation, or after some time delay (of the order of larger than 100 ns for occurrence of CN in CO 2 :N 2 gas mixtures) from optical breakdown when using nanosecond laser pulses. Just like for atomic spectra, reasonably accurate molecular spectra are required for analysis [12][13][14][15][16]. The construction of a molecular spectrum relies on: (i) accurate line positions, and (ii) reasonably accurate transition strengths [17][18][19][20].…”