Letter | Published:

Rotational state-changing cold collisions of hydroxyl ions with helium

Nature Physics volume 11, pages 467470 (2015) | Download Citation

  • A Corrigendum to this article was published on 03 November 2015

This article has been updated

Abstract

Cold molecules are important for many applications1, from fundamental precision measurements2, quantum information processing3, quantum-controlled chemistry4, to understanding the cold interstellar medium5. Molecular ions are known to be cooled efficiently in sympathetic collisions with cold atoms or ions6,7,8. However, little knowledge is available on the elementary cooling steps, because the determination of quantum state-to-state collision rates at low temperature is very challenging for both experiment and theory. Here we present a method to manipulate molecular quantum states by non-resonant photodetachment. Based on this we provide absolute quantum scattering rate coefficients under full quantum state control for the rotationally inelastic collision of hydroxyl anions with helium. Experiment and quantum scattering theory show reasonable agreement without adjustable parameters. Very similar rate coefficients are obtained for two different isotopes, which is linked to several quantum scattering resonances appearing at different energies. The presented method is also applicable to polyatomic systems and will help elucidate non-radiative processes in polyaromatic hydrocarbons and protein chromophores.

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Change history

  • 01 October 2015

    In the version of this Letter originally published the given rotational temperature of the trapped anions was obtained with an incorrect fit function, which also resulted in an overestimation of the measured inelastic rate coefficients. The correct rotational temperature is 22 K. With this rotational temperature the fit to the depletion data yields smaller inelastic collision rates, which are shown in Fig. 2c, and smaller measured inelastic collision rate coefficients, which are shown in Fig. 3b. The measured rate coefficients are slightly smaller than the computed rate coefficients. Quantitative agreement is confirmed for the ratio of the computed and measured rate coefficients for the OH and OD isotopes. These errors have been corrected in the online versions of the Letter.

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Acknowledgements

This work has been supported by the European Research Council under ERC grant agreement No. 279898. E.S.E. acknowledges support from the Fond National de la Recherche Luxembourg. We also acknowledge the High-Performance Computing Centre at the University of Innsbruck.

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Affiliations

  1. Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria

    • Daniel Hauser
    • , Seunghyun Lee
    • , Fabio Carelli
    • , Steffen Spieler
    • , Olga Lakhmanskaya
    • , Eric S. Endres
    • , Sunil S. Kumar
    • , Franco Gianturco
    •  & Roland Wester

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Contributions

D.H., S.L., O.L., S.S., E.S.E. and S.S.K. performed the experiments. F.C. and F.G. carried out the calculations. R.W. planned and supervised the project. D.H., F.C., S.S.K. and R.W. prepared the manuscript with input from all authors.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Roland Wester.

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https://doi.org/10.1038/nphys3326

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