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arXiv · 1902.05459

Excitation of the $^{229}$Th nucleus via a two-photon electronic transition

Robert A. Müller·Andrey V. Volotka·Andrey Surzhykov
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Abstract

We investigate the process of nuclear excitation via a two-photon electron transition (NETP) for the case of the doubly charged thorium. The theory of the NETP process has been devised originally for heavy helium-like ions. In this work, we study this process in the nuclear clock isotope $^{229}$Th in the $2+$ charge state. For this purpose, we employ a combination of configuration interaction and many-body perturbation theory to calculate the probability of NETP in resonance approximation. The experimental scenario we propose for the excitation of the low lying isomeric state in $^{229}$Th is a circular process starting with a two-step pumping stage followed by NETP. The ideal intermediate steps in this process depend on the supposed energy $\hbar\omega_N$ of the nuclear isomeric state. For each of these energies, the best initial state for NETP is calculated. Special focus is put on the most recent experimental results for $\hbar\omega_N$.

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Robert A. Müller, Andrey V. Volotka, Andrey Surzhykov. 2019-02-14. Excitation of the $^{229}$Th nucleus via a two-photon electronic transition. https://doi.org/10.1103/physreva.99.042517

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