Precise and accurate nuclear electric quadrupole moment of 223Ra from molecular spectroscopy
Abstract
Nuclear electric quadrupole moments of unstable isotopes are commonly extracted from laser spectroscopy of the atomic hyperfine structure, where the accuracy is limited to the several-percent level by the available electric-field-gradient (EFG) calculations. In this study, we determine the spectroscopic quadrupole moment of 223Ra (half-life t1/2 = 11.4 d) from hyperfine-resolved collinear resonance ionization spectroscopy of the radioactive molecule 223Ra19F. The X 2Σ+ electronic ground state of RaF provides a large axial EFG at the radium nucleus that can be calculated with relativistic coupled-cluster theory to sub-percent accuracy. Together with a three-fold improvement in spectral resolution over previous fast-beam measurements of radioactive molecules, this yields Qs = +1.211(7)stat(2)syst(5)theo eb for 223Ra with a total uncertainty of 0.73%, approximately three times better than atomic and ionic determinations. This result demonstrates that molecular spectroscopy can provide access to the electromagnetic structure of unstable nuclei with a precision competitive with, and in favorable cases better than, atomic spectroscopy, and may thus be envisioned for studies beyond the limitations of current radioactive-atom experiments.
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BibTeX
@misc{fajardozambrano2026precise,
title = {{Precise and accurate nuclear electric quadrupole moment of $^223$Ra from molecular spectroscopy}},
author = {C. M. Fajardo-Zambrano and M. Athanasakis-Kaklamanakis and L. Lalanne and J. R. Reilly and O. Ahmad and M. Au and S. W. Bai and J. Berbalk and C. Bernerd and A. A. Breier and K. Chrysalidis and T. E. Cocolios and R. P. de Groote and K. T. Flanagan and S. Franchoo and R. F. Garcia Ruiz and R. Heinke and P. Imgram and Á. Koszorús and P. Lassègues and J. Lim and Y. C. Liu and K. M. Lynch and A. McGlone and W. C. Mei and G. Neyens and L. Nies and A. Raggio and S. Rothe and B. van den Borne and J. Warbinek and J. Wessolek and X. F. Yang},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.04696},
eprint = {2611.04696},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.04696},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Precise and accurate nuclear electric quadrupole moment of ^223Ra from molecular spectroscopy
AU - C. M. Fajardo-Zambrano
AU - M. Athanasakis-Kaklamanakis
AU - L. Lalanne
AU - J. R. Reilly
AU - O. Ahmad
AU - M. Au
AU - S. W. Bai
AU - J. Berbalk
AU - C. Bernerd
AU - A. A. Breier
AU - K. Chrysalidis
AU - T. E. Cocolios
AU - R. P. de Groote
AU - K. T. Flanagan
AU - S. Franchoo
AU - R. F. Garcia Ruiz
AU - R. Heinke
AU - P. Imgram
AU - Á. Koszorús
AU - P. Lassègues
AU - J. Lim
AU - Y. C. Liu
AU - K. M. Lynch
AU - A. McGlone
AU - W. C. Mei
AU - G. Neyens
AU - L. Nies
AU - A. Raggio
AU - S. Rothe
AU - B. van den Borne
AU - J. Warbinek
AU - J. Wessolek
AU - X. F. Yang
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.04696
UR - https://arxiv.org/abs/2611.04696
AB - Nuclear electric quadrupole moments of unstable isotopes are commonly extracted from laser spectroscopy of the atomic hyperfine structure, where the accuracy is limited to the several-percent level by the available electric-field-gradient (EFG) calculations. In this study, we determine the spectroscopic quadrupole moment of ^223Ra (half-life t_1/2 = 11.4 d) from hyperfine-resolved collinear resonance ionization spectroscopy of the radioactive molecule ^223Ra^19F. The X ^2Σ^+ electronic ground state of RaF provides a large axial EFG at the radium nucleus that can be calculated with relativistic coupled-cluster theory to sub-percent accuracy. Together with a three-fold improvement in spectral resolution over previous fast-beam measurements of radioactive molecules, this yields Q_s = +1.211(7)_stat(2)_syst(5)_theo eb for ^223Ra with a total uncertainty of 0.73%, approximately three times better than atomic and ionic determinations. This result demonstrates that molecular spectroscopy can provide access to the electromagnetic structure of unstable nuclei with a precision competitive with, and in favorable cases better than, atomic spectroscopy, and may thus be envisioned for studies beyond the limitations of current radioactive-atom experiments.
ER -