Analytic Relativistic Coupled-cluster Calculations Of Time-reversal Violating Parameters

Abstract

We report an analytic scheme for relativistic exact two-component coupled-cluster singles and doubles with a noniterative triples [X2C-CCSD(T)] calculations of electric effective field, $\varepsilon_{\text{eff}}$, a time-reversal symmetry-violating parameter that plays a key role in the interpretation of experimental precision measurement of paramagnetic atoms and molecules for electron electric dipole moment (eEDM) search. Benchmark X2C-CCSD(T) calculations for the $\varepsilon_{\text{eff}}$ values of twenty-one heavy-metal containing small molecules demonstrate the efficacy and accuracy of the present scheme. The computational results show that metal methoxides including BaOCH$_3$, YbOCH$_3$, and RaOCH$_3$ possess large $\varepsilon_{\text{eff}}$ values similar to those of the corresponding fluorides and hydroxides, supporting the recent proposal of using nearly degenerate rotational states of these symmetric-top molecules to enhance the sensitivity of eEDM measurement. The present analytic scheme enables fast and reliable initial screening of candidate molecules for the eEDM search.