Communications Chemistry (May 2024)

Dual-comb spectroscopy of ammonia formation in non-thermal plasmas

  • Ibrahim Sadiek,
  • Adam J. Fleisher,
  • Jakob Hayden,
  • Xinyi Huang,
  • Andreas Hugi,
  • Richard Engeln,
  • Norbert Lang,
  • Jean-Pierre H. van Helden

DOI
https://doi.org/10.1038/s42004-024-01190-7
Journal volume & issue
Vol. 7, no. 1
pp. 1 – 10

Abstract

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Abstract Plasma-activated chemical transformations promise the efficient synthesis of salient chemical products. However, the reaction pathways that lead to desirable products are often unknown, and key quantum-state-resolved information regarding the involved molecular species is lacking. Here we use quantum cascade laser dual-comb spectroscopy (QCL-DCS) to probe plasma-activated NH3 generation with rotational and vibrational state resolution, quantifying state-specific number densities via broadband spectral analysis. The measurements reveal unique translational, rotational and vibrational temperatures for NH3 products, indicative of a highly reactive, non-thermal environment. Ultimately, we postulate on the energy transfer mechanisms that explain trends in temperatures and number densities observed for NH3 generated in low-pressure nitrogen-hydrogen (N2–H2) plasmas.