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Vibrationally highly excited trilobite molecules stabilized by nonadiabatic coupling

Rohan Srikumar1,*, Markus Exner2,*, Richard Blättner2, Peter Schmelcher1,3, Matthew T. Eiles4, and Herwig Ott2,†

  • *These authors contributed equally to this work.
  • †Contact author: ott@physik.uni-kl.de
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Phys. Rev. Research 7, 043103 – Published 27 October, 2025

DOI: https://doi.org/10.1103/49ky-d8mm

Abstract

We report on the observation of highly excited (ν∼100) vibrational states of a trilobite ultralong-range Rydberg molecule in Rb87. These states manifest spectroscopically in a regularly spaced series of peaks red-detuned from the 25f7/2 dissociation threshold. The existence and observed stability of these states require the almost complete suppression of the adiabatic decay pathway induced by the P-wave shape resonance of Rb. This stabilization is predicted to occur only for certain Rydberg levels where the avoided crossing between trilobite and P-wave-dominated butterfly potential energy curves nearly vanishes, allowing the vibrational states to diabatically traverse the crossing with almost unit probability. This is the first direct measurement of beyond-Born-Oppenheimer physics in long-range Rydberg molecules, and paves the way for future experiments to access and manipulate wave packets formed from high-lying vibrational states.

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Phys. Rev. Research 7, 043103– Published 27 October, 2025
  • Received 21 April 2025
  • Accepted 15 September 2025
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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.

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