Long-wave infrared laser-induced breakdown spectroscopy of complex gas molecules in the vicinity of a laser-induced plasma

Clayton S-C Yang; Feng Jin; Sudhir Trivedi; Uwe Hommerich; Laszlo Nemes; Alan C Samuels

doi:10.1016/j.saa.2023.122536

Long-wave infrared laser-induced breakdown spectroscopy of complex gas molecules in the vicinity of a laser-induced plasma

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Jun 5:294:122536. doi: 10.1016/j.saa.2023.122536. Epub 2023 Feb 21.

Authors

Clayton S-C Yang¹, Feng Jin², Sudhir Trivedi², Uwe Hommerich³, Laszlo Nemes⁴, Alan C Samuels⁵

Affiliations

¹ Brimrose Corporation of America, Baltimore, MD 21152, USA. Electronic address: cyang@brimrose.com.
² Brimrose Corporation of America, Baltimore, MD 21152, USA.
³ Department of Physics Hampton University, Hampton, VA 23668, USA.
⁴ Research Center for Natural Sciences, Institute of Materials and Environmental Chemistry, Hungarian Academy of Sciences, Budapest 1519, Hungary.
⁵ Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD 21010, USA.

PMID: 36841136
DOI: 10.1016/j.saa.2023.122536

Abstract

Vibration-rotation signatures of intact water and complex organic molecules in vapor phase were detected, identified, and mode-assigned in the long-wave infrared emissions of laser-induced plasma. Time resolved long-wave infrared emissions were also studied to assess the temporal behaviors of these gaseous molecular emitters. The temperatures of these molecular vapors in the hot and transient vapor-plasma plume of the laser-induced plasma were estimated to be well above room temperatures during their existence. The temperatures of the water vapors in the vapor-plasma plume were found to be evolving with time and ranging from > 2700 K at 10 µs to ∼ 1500 K at 200 µs after plasma initiations using HITRAN/HAPI based molecular spectral analysis. The observations in the present study comprise (to our knowledge) the first direct evidence of hot water and intact complex organic gas molecules in the vicinity of the laser-induced plasma. The findings presented in this work serve as an important step forward in improving the understanding of the thermodynamic characteristics (such as temperatures and phases) of intact complex molecules in a hot and intricate system such as the vapor-plasma plume of a laser-induced plasma, which is essential in both fundamental studies of plasmas and of laser-induced plasma based analytical applications.

Keywords: Atomic emission; Laser-induced breakdown spectroscopy; Laser-induced plasma; Long-wave infrared spectroscopy; Molecular emission.