Vibrationally-dependent molecular dynamics in mutual neutralisation reactions of molecular oxygen ions
Product distributions and dynamics of low-collision-energy mutual neutralisation reactions involving even simple molecular ions are largely unknown. Reactions which involve oxygen ions, e.g., <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>O</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mo>+</mml:mo></mml:mrow> </mml:msubsup> </mml:math> with O<sup>-</sup>, are expected to be important in atmospheric phenomena such as sprites and in high-pressure air or oxygen discharges. Here we show, by combining cryogenically stored-and-merged ion beams with coincident product-imaging techniques, that the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>O</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mo>+</mml:mo></mml:mrow> </mml:msubsup> </mml:math> with O<sup>-</sup> mutual neutralisation reaction results predominantly in dissociation of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>O</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mo>+</mml:mo></mml:mrow> </mml:msubsup> </mml:math> molecule. Three competing reaction pathways yields both O(<sup>3</sup>P) (84%) and O(<sup>1</sup>D) (16%) products, but no O(<sup>1</sup>S) products. Analysis of the momentum-correlated dynamics of the reaction reveals the dominance of two-step mechanisms involving the 3pλ<sub>u</sub> and 3sσ<sub>g</sub> Rydberg states of O<sub>2</sub>. Furthermore, use of the <sup>16,18</sup> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>O</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mo>+</mml:mo></mml:mrow> </mml:msubsup> </mml:math> isotopologue shows that the reaction products strongly depend on the vibrational levels of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mi>O</mml:mi></mml:mrow> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mo>+</mml:mo></mml:mrow> </mml:msubsup> </mml:math> ion for the channel leading to two O(<sup>1</sup>D) products.
Authors
- Henning T. Schmidt (ORCID: https://orcid.org/0000-0002-8209-5095)
- Nicholas S. Shuman (ORCID: https://orcid.org/0000-0002-0274-2644)
- Mats Larsson (ORCID: https://orcid.org/0000-0001-9784-4151)
- MingChao Ji (ORCID: https://orcid.org/0000-0001-8184-4595)
- Mathias Poline (ORCID: https://orcid.org/0000-0003-4515-9691)
- Shaun G. Ard (ORCID: https://orcid.org/0000-0001-8562-1583)
- H. Cederquist (ORCID: https://orcid.org/0000-0002-0815-0658)
- Richard Thomas (ORCID: https://orcid.org/0000-0002-9145-6366)
- Stefan Rosén (ORCID: https://orcid.org/0009-0001-7448-0030)
- Henning Zettergren (ORCID: https://orcid.org/0000-0002-2493-4161)
- Albert A. Viggiano (ORCID: https://orcid.org/0000-0002-8638-2446)
- Arnaud Dochain
Institutions
- United States Air Force Research Laboratory (US)
- Stockholm University (SE)
- Kirtland Air Force Base (US)
- UCLouvain (BE)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-09-26
- DOI
- https://doi.org/10.1038/s41467-025-64198-0
- Citations
- 1
- Primary Topic
- Spectroscopy and Laser Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.76
Funders
- Knut och Alice Wallenbergs Stiftelse
- Vetenskapsrådet
- Stockholms Universitet
- Air Force Office of Scientific Research