Laser Resonance Chromatography of $^{229}$Th$^{3+}$ in He: an ab initio investigation

TL;DR

This paper models ion-neutral interactions of $^{229}$Th$^{3+}$ in helium to propose a laser resonance chromatography method for detecting specific electronic states relevant to nuclear clock transition studies.

Contribution

It introduces a relativistic ab initio approach to simulate ion mobilities for different electronic states of $^{229}$Th$^{3+}$, enabling state-specific separation via LRC.

Findings

Ion mobilities differ by over 7% at 300 K and moderate fields.

Simulation shows feasibility of separating metastable states with LRC.

Provides a theoretical foundation for experimental detection of nuclear clock transitions.

Abstract

We propose a laser resonance chromatography (LRC) experiment on $^{229}$Th$^{3+}$, with the goal of detecting the ion's electronic ground $5f$ $^2$F$_{5/2}$ state and metastable $7s$ $^2$S$_{1/2}$ state by means of their ion mobilities. To this end, we first model the ion-neutral interaction potentials for the two electronic states with a relativistic Fock space coupled cluster method and complete basis-set extrapolation scheme. The interaction potentials are used to simulate the state-specific reduced ion mobilities in terms of the operating temperature and the external electric field. The ion mobilities differ by more than 7% at 300 K and moderate field strengths; thus, separation of the $^{229}$Th$^{3+}$ metastable state lies within the reach of LRC experiments targeting optical probing and monitoring of the nuclear clock transition in this isotope.