Nuclear Charge Radii of Sr Isotopes: Reevaluation based on Transition Frequency Measurements in the 5s−5p−4d manifold in Sr+
Abstract
High-precision quasi-simultaneous collinear and anticollinear laser spectroscopy was performed on the 5s 2S1/2→ 5p 2P1/2 (D1), 5s 2S1/2→ 5p 2P3/2 (D2), and three 4d→ 5p transitions in the naturally abundant Sr+ isotopes. Absolute transition frequencies were determined with uncertainties as low as $600$ kHz, while common-mode rejection enabled the extraction of isotope shifts with uncertainties down to $200$ kHz, one order of magnitude smaller than previously achieved. The uncertainties of the hyperfine-structure constants of the 5p states and the 4d 2D3/2 state in 87Sr were also improved. A King-plot analysis yielded a field-shift ratio of the D2 and D1 lines of FD2/FD1=1.004(5), which lies within the theoretically allowed region and provides a benchmark for atomic-structure calculations. Using data from all stable isotopes and investigated transitions, we compare field- and mass-shift constants obtained using several established approaches, ranging from King plots based entirely on experimental input to state-of-the-art \textit{ab initio} atomic-structure calculations. We show that, above N=50, the extracted charge radii depend strongly on the approach used.
Versions
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BibTeX
@misc{palmes2026nuclear,
title = {{Nuclear Charge Radii of Sr Isotopes: Reevaluation based on Transition Frequency Measurements in the $5s-5p-4d$ manifold in Sr$^+$}},
author = {J. Palmes and K. König and B. K. Sahoo and H. Bodnar and A. Candiello and A. Dorne and R. de Groote and P. Imgram and I. Lopp and P. Müller and W. Nörtershäuser and B. Ohayon and R. Van Duyse},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2605.04281},
eprint = {2605.04281},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.04281},
}
RIS
TY - UNPB
TI - Nuclear Charge Radii of Sr Isotopes: Reevaluation based on Transition Frequency Measurements in the 5s−5p−4d manifold in Sr^+
AU - J. Palmes
AU - K. König
AU - B. K. Sahoo
AU - H. Bodnar
AU - A. Candiello
AU - A. Dorne
AU - R. de Groote
AU - P. Imgram
AU - I. Lopp
AU - P. Müller
AU - W. Nörtershäuser
AU - B. Ohayon
AU - R. Van Duyse
PY - 2026
DA - 2026/08/04
PB - arXiv
DO - 10.48550/arxiv.2605.04281
UR - https://arxiv.org/abs/2605.04281
AB - High-precision quasi-simultaneous collinear and anticollinear laser spectroscopy was performed on the 5s ^2S_1/2→ 5p ^2P_1/2 (D1), 5s ^2S_1/2→ 5p ^2P_3/2 (D2), and three 4d→ 5p transitions in the naturally abundant Sr^+ isotopes. Absolute transition frequencies were determined with uncertainties as low as $600$ kHz, while common-mode rejection enabled the extraction of isotope shifts with uncertainties down to $200$ kHz, one order of magnitude smaller than previously achieved. The uncertainties of the hyperfine-structure constants of the 5p states and the 4d ^2D_3/2 state in ^87Sr were also improved. A King-plot analysis yielded a field-shift ratio of the D2 and D1 lines of F_D2/F_D1=1.004(5), which lies within the theoretically allowed region and provides a benchmark for atomic-structure calculations. Using data from all stable isotopes and investigated transitions, we compare field- and mass-shift constants obtained using several established approaches, ranging from King plots based entirely on experimental input to state-of-the-art \textit{ab initio} atomic-structure calculations. We show that, above N=50, the extracted charge radii depend strongly on the approach used.
ER -