# Reevaluation of the nuclear electric quadrupole moment for 87Sr by hyperfine structures and relativistic atomic theory

## TL;DR

This paper reevaluates the nuclear electric quadrupole moment of 87Sr using hyperfine structure data and relativistic atomic theory, providing a new, more accurate value that aligns with some previous results.

## Contribution

The study introduces a new, precise value for the 87Sr quadrupole moment using advanced atomic calculations and hyperfine data, improving upon previous estimates.

## Key findings

- New quadrupole moment value: 328(4) mb.
- Calculated electric field gradients with ~1% uncertainty.
- Result aligns with some prior experimental and theoretical values.

## Abstract

The values of nuclear electric quadrupole moment are different by about 7% for 87Sr nucleus between the recommended value [N. J. Stone, At. Data Nucl. Data Tables 111-112, 1 (2016); P. Pyykko, Mol. Phys. 116, 1328 (2018)] and earlier results [e.g. A. M. Matensson-Pendrill, J. Phys. B: At. Mol. Opt. Phys. 35, 917 (2002); K. Z. Yu et al., Phys. Rev. A 70, 012506 (2004)]. In this work, we reported a new value, Q(87Sr) = 328(4) mb, making use of our calculated electric field gradients produced by electrons at nucleus in combination with experimental values for hyperfine structures of the 5s5p 3P1,2 states of the neutral Sr atom. In the framework of the multi-configuration Dirac-Hartree-Fock theory, the electron correlations were taken into account systematically so as to control the uncertainties of the electric field gradient at about 1% level. The present result is different from the recommended value, but in excellent agreement with those by Matensson-Pendrill and Yu et al.. We would recommend the present Q value as a reference for 87Sr.