A relativistic unitary coupled-cluster study of electric quadrupole moment and magnetic dipole hyperfine constants of ^{199}Hg^{+}

TL;DR

This paper employs a relativistic unitary coupled-cluster approach to accurately calculate electric quadrupole and hyperfine constants of ^{199}Hg^{+}, aiding the development of next-generation optical atomic clocks.

Contribution

It introduces the first application of a variant of coupled-cluster theory to study electric quadrupole and hyperfine properties of ^{199}Hg^{+}, providing the most accurate estimates to date.

Findings

Calculated electric quadrupole moment of the 5d^{9}6s^{2} ^{2}D_{5/2} state.

Determined magnetic dipole hyperfine constants for multiple states of ^{199}Hg^{+}.

Results show improved agreement with available experimental data.

Abstract

Searching for an accurate optical clock which can serve as a better time standard than the present day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to built more accurate clocks with different ion species. In this article we discuss the electric quadrupole and hyperfine shifts in the $5d^{9}6s^{2} ^{2}D_{5/2}(F=0,m_{F}=0)\leftrightarrow5d^{10}6s ^{2}S_{1/2}(F=2,m_{F}=0)$ clock transition in $ ^{199}Hg^{+}$, one of the most promising candidates for next generation optical clocks. We have applied Fock-space unitary coupled-cluster (FSUCC) theory to study the electric quadrupole moment of the $5d^{9}6s^{2} ^{2}D_{5/2}$ state and magnetic dipole hyperfine constants of $5d^{9}6s^{2} ^{2}D_{3/2,5/2}$ and $5d^{10}6s^{1} ^{2}S_{1/2}$ states respectively of $ ^{199}Hg^{+}$. We have also compared our results with available data. To the best of our knowledge, this is the first time a variant of coupled-cluster (CC) theories has been applied to study these kinds of properties of $Hg^{+}$and is the most accurate estimate of these quantities to date.