# Enhancement factor for the electric dipole moment of the electron in the BaOH and YbOH molecules

## TL;DR

This study calculates the electric dipole moment enhancement factor ($E_ ext{eff}$) in BaOH and YbOH molecules using high-accuracy relativistic methods, showing their potential for future fundamental symmetry violation experiments.

## Contribution

First high-accuracy relativistic calculations of $E_ ext{eff}$ in triatomic BaOH and YbOH molecules, demonstrating their suitability for electron EDM searches.

## Key findings

- $E_ ext{eff}$ in BaOH is 6.65 GV/cm
- $E_ ext{eff}$ in YbOH is 23.4 GV/cm
- Triatomic molecules have similar $E_ ext{eff}$ to diatomic counterparts

## Abstract

Polyatomic polar molecules are promising systems for future experiments that search for violation of time-reversal and parity symmetries due to their advantageous electronic and vibrational structure, which allows laser cooling, full polarisation of the molecule, and reduction of systematic effects [I. Kozyryev and N.R. Hutzler, Phys, Rev. Lett. {\bf 119}, 133002 (2017)]. In this work we investigate the enhancement factor of the electric dipole moment of the electron ($E_\text{eff}$) in the triatomic monohydroxide molecules BaOH and YbOH within the high-accuracy relativistic coupled cluster method. The recommended $E_\text{eff}$ values of the two systems are 6.65 $\pm$ 0.15 GV/cm and 23.4 $\pm$ 1.0 GV/cm, respectively. We compare our results with similar calculations for the isoelectronic diatomic molecules BaF and YbF, which are currently used in experimental search for $P,T$-odd effects in molecules. The $E_\text{eff}$ values prove to be very close, within about 1.5 $\%$ difference in magnitude between the diatomic and the triatomic compounds. Thus, BaOH and YbOH have a similar enhancement of the electron electric dipole moment, while benefiting from experimental advantages, and can serve as excellent candidates for next-generation experiments.