Nuclear anapole moment interaction in BaF from relativistic coupled-cluster theory

We present high-accuracy relativistic coupled-cluster calculations of the P-odd interaction coefficient W-A describing the nuclear anapole moment effect on the molecular electronic structure. The molecule under study, BaF, is considered a promising candidate for the measurement of the nuclear anapole moment, and the preparation for the experiment is now underway [E. Altuntas et al., Phys. Rev. Lett. 120, 142501 (2018)]. The influence of various computational parameters (size of the basis set, treatment of relativistic effects, and treatment of electron correlation) on the calculated W-A coefficient is investigated and a recommended value of 147.7 Hz with an estimated uncertainty of 1.5% is proposed.