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arXiv · 1705.00869

Precision measurement of the rotational energy-level structure of the three-electron molecule He$_2^+$

Luca Semeria·Paul Jansen·Frédéric Merkt
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Abstract

The term values of all rotational levels of the $^4$He${_2}^+\,X^+\,^2Σ_u^+\,(ν^+=0)$ ground vibronic state with rotational quantum number $N^+\le 19$ have been determined with an accuracy of 8 x 10$^{-4}$ cm$^{-1}$ ($\sim{25}$ MHz) by MQDT-assisted Rydberg spectroscopy of metastable He$_2^*$. Comparison of these term values with term values recently calculated ab initio by Tung et al. [J. Chem. Phys. 136, 104309 (2012)] reveal discrepancies that rapidly increase with increasing rotational quantum number and reach values of 0.07 cm$^{-1}$ ($\sim{2.1}$ GHz) at $N^+=19$.

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Luca Semeria, Paul Jansen, Frédéric Merkt. 2017-05-02. Precision measurement of the rotational energy-level structure of the three-electron molecule He$_2^+$. https://doi.org/10.1063/1.4967256

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