Mercury Monohalides: Suitability for Electron Electric Dipole Moment Searches

TL;DR

This paper presents relativistic ab initio calculations of effective electric fields in mercury monohalides, identifying HgBr and HgI as promising molecules for electron EDM search experiments due to their high sensitivity.

Contribution

It provides the first detailed theoretical analysis of the effective electric fields in mercury monohalides relevant for eEDM experiments, highlighting new candidate molecules.

Findings

HgBr and HgI have large effective electric fields suitable for eEDM searches.

The halide anions influence the effective electric field significantly.

Relativistic effects are crucial for accurate predictions in these molecules.

Abstract

Heavy polar diatomic molecules are the primary tools for searching for the T-violating permanent electric dipole moment of the electron (eEDM). Valence electrons in some molecules experience extremely large effective electric fields due to relativistic interactions. These large effective electric fields are crucial to the success of polar-molecule-based eEDM search experiments. Here we report on the results of relativistic ab initio calculations of the effective electric fields in a series of molecules that are highly sensitive to an eEDM, the mercury monohalides (HgF, HgCl, HgBr,and HgI). We study the influence of the halide anions on effective electric field, and identify HgBr and HgI as interesting candidates for future electric dipole moment search experiments.