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Initial-state control in mutual neutralization of Si− with Na+ or K+ revealing strong violations of Wigner's spin-conservation rule

Rachel Poulose1,*, Åsa Larson1, Paul Martini1, MingChao Ji1, Ansgar Simonsson1, Stéfan Rosen1, Mikael Björkhage1, Peter Reinhed1, Mikael Blom1 et al.

Jose Eduardo Navarro Navarrete1, Sadiq Muhammad1, Julia Karls2, Arnaud Dochain3, Henning Zettergren1, Henrik Cederquist1, Dag Hanstorp2, and Henning T. Schmidt1,†

  • *Contact author: rachel.poulose@fysik.su.se
  • †Contact author: schmidt@fysik.su.se
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Phys. Rev. A 113, 042819 – Published 20 April, 2026

DOI: https://doi.org/10.1103/dpy6-pbz2

Abstract

We have studied low-energy mutual neutralization in reactions of Si− with Na+ and with K+ ions at the merged-beam double ion-beam storage-ring facility DESIREE. We made measurements with and without a significant fraction of the Si− ions in the metastable D2 level. The latter was achieved by state-selective photodetachment. The data reveal contributions from spin-forbidden mutual-neutralization reactions, i.e., violations of Wigner's spin-conservation rule. For the Na++Si− case, the dominating such reaction channel is obscured when metastable Si− ions are present in the beam.

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Phys. Rev. A 113, 042819– Published 20 April, 2026
  • Received 9 December 2025
  • Accepted 5 March 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by Bibsam.

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