Revisiting Nuclear Quadrupole Moments in $^{39-41}$K Isotopes

TL;DR

This paper provides more precise evaluations of nuclear quadrupole moments for potassium isotopes using advanced relativistic calculations, challenging existing standard values and offering new hyperfine structure data.

Contribution

It introduces a refined computational approach to determine nuclear quadrupole moments and hyperfine constants, revealing discrepancies with standard nuclear data.

Findings

Revised quadrupole moments for $^{39}$K, $^{40}$K, and $^{41}$K.

Disagreement with standard nuclear data values.

First-time calculations of hyperfine constants for several excited states.

Abstract

Nuclear quadrupole moments ($Q$s) in three isotopes of potassium (K) with atomic mass numbers 39, 40 and 41 are evaluated more precisely in this work. The $Q$ value of $^{39}$K is determined to be 0.0614(6) $b$ by combining the available experimental result of the electric quadrupole hyperfine structure constant ($B$) with our calculated $B/Q$ result of its $4P_{3/2}$ state. Furthermore combining this $Q$ value with the measured ratios $Q$($ ^{40}$K)$/Q$($ ^{39}$K) and $Q$($ ^{41}$K)$/Q$($ ^{39}$K), we obtain $Q$($ ^{40}$K)$=-0.0764(10) \ b$ and $Q$($ ^{41}$K)$=0.0747(10) \ b$, respectively. These results disagree with the recently quoted standard values in the nuclear data table within the given uncertainties. The calculations are carried out by employing the relativistic coupled-cluster theory at the singles, doubles and involving important valence triples approximation. The accuracies of the calculated $B/Q$ results can be viewed on the basis of comparison between our calculated magnetic dipole hyperfine structure constants ($A$s) with their corresponding measurements for many low-lying states. Both $A$ and $B$ results in few more excited states are presented for the first time.