Calculations of Time-Reversal Symmetry Violation Sensitivity Parameters Based on Analytic Relativistic Coupled-Cluster Gradient Theory.

We develop an analytic-gradient-based method for relativistic coupled-cluster calculations of effective electric field ${\mathcal{E}}_{\text{eff}}$ with improved efficiency and robustness over the previous state of the art. The enhanced capability to calculate this time-reversal-symmetry-violation sensitivity parameter enables efficient screening of candidate molecules for the electron electric dipole moment (eEDM) search. As examples, the $|{\mathcal{E}}_{\text{eff}}|$ values of metal methoxides including ${\mathrm{BaOCH}}_{3}$, ${\mathrm{YbOCH}}_{3}$, and ${\mathrm{RaOCH}}_{3}$ are shown to be as large as those of the corresponding fluorides and hydroxides, which supports the recent proposal of using these symmetric-top molecules to improve the sensitivity of eEDM measurements. The computational results also show that molecules containing late actinide elements, NoF, NoOH, LrO, and ${\mathrm{LrOH}}^{+}$, exhibit particularly large $|{\mathcal{E}}_{\text{eff}}|$ values of around 200 GV/cm.