# Theoretical study on the hyperfine interaction constants and the isotope shift factors for the $3s^2~^1 S_{ 0} ~-~ 3s3p~^{3,1}P^o_1$ transitions in Al$^+$

## TL;DR

This theoretical study calculates hyperfine interaction constants and isotope shift factors for specific transitions in Al$^+$ ions, providing precise atomic parameters crucial for nuclear property analysis.

## Contribution

It offers detailed multiconfiguration Dirac-Hartree-Fock calculations of hyperfine and isotope shift parameters, including electron correlation and relativistic effects, with uncertainties below 1.5%.

## Key findings

- Hyperfine constants have uncertainties less than 1.5%.
- Electron correlations significantly affect isotope shift factors.
- Relativistic nuclear recoil corrections are negligible for Al$^+$.

## Abstract

We calculated the magnetic dipole and the electric quadrupole hyperfine interaction constants of 3s3p $^{3,1}P^o_1$ states and the isotope shift, including mass and field shift, factors for transitions from these two states to the ground state 3s$^2~^1S_0$ in Al$^+$ ions using the multiconfiguration Dirac-Hartree-Fock method. The effects of the electron correlations and the Breit interaction on these physical quantities were investigated in detail based on the active space approach. It is found that the CC and the higher-order correlations are considerable for evaluating the uncertainties of the atomic parameters concerned. The uncertainties of the hyperfine interaction constants in this work are less than 1.5\%. Although the isotope shift factors are highly sensitive to the electron correlations, reasonable uncertainties were obtained by exploring the effects of the electron correlations. Moreover, we found that the relativistic nuclear recoil corrections to the mass shift factors are very small and insensitive to the electron correlations for Al$^{+}$. These atomic parameters present in this work are valuable for extracting the nuclear electric quadrupole moments and the mean-square charge radii of Al isotopes.