Spectroscopy on the eEDM-sensitive states of ThF$^+$

TL;DR

This study conducts spectroscopy on ThF$^+$ to determine key constants for eEDM measurement, assesses vibrational state lifetimes, and discusses implications for future experiments at JILA.

Contribution

It provides the first detailed spectroscopic constants for ThF$^+$'s eEDM-sensitive state and evaluates vibrational lifetimes relevant for precision measurements.

Findings

Measured hyperfine coupling, dipole moment, and g-factor of ThF$^+$

Determined vibrational state lifetime and impact of blackbody radiation

Compared ab initio calculations with experimental results

Abstract

An excellent candidate molecule for the measurement of the electron's electric dipole moment (eEDM) is thorium monofluoride (ThF$^+$) because the eEDM-sensitive state, $^3\Delta_1$, is the electronic ground state, and thus is immune to decoherence from spontaneous decay. We perform spectroscopy on $X\,^3\Delta_1$ to extract three spectroscopic constants crucial to the eEDM experiment: the hyperfine coupling constant, the molecular frame electric dipole moment, and the magnetic $g$-factor. To understand the impact of thermal blackbody radiation on the vibrational ground state, we study the lifetime of the first excited vibrational manifold of $X\,^3\Delta_1$. We perform ab initio calculations, compare them to our results, and discuss prospects for using ThF$^+$ in a new eEDM experiment at JILA.