Relativistic coupled-cluster study of RaF as a candidate for the parity- and time-reversal-violating interaction

Abstract

We have employed both Z-vector method and the expectation value approach in the relativistic coupled-cluster framework to calculate the scalar-pseudoscalar (S-PS) P, T -odd interaction constant (Ws) and the effective electric field (E eff ) experienced by the unpaired electron in the ground electronic state of RaF. Further, the magnetic hyperfine structure constants of 223 Ra in RaF and 223 Ra + are also calculated and compared with the experimental values wherever available to judge the extent of accuracy obtained in the employed methods. The outcome of our study reveals that the Z-vector method is superior than the expectation value approach in terms of accuracy obtained for the calculation of ground state property. The Z-vector calculation shows that RaF has a high E eff (52.5 GV/cm) and Ws (141.2 kHz) which makes it a potential candidate for the eEDM experiment.

Zeroth order regular approximation approach to electric dipole moment interactions of the electron

“…21,22 The theoretical search for still more favourable candidates for eEDM experiments, employing relativistic quantum chemistry, is vivid. [23][24][25][26][27][28][29][30] So far, besides the strong Z-dependence of CP-violating effects, there appears to be no thorough understanding of the mecha-nisms that make eEDM enhancement in molecular systems large, but first attempts in this direction have been reported recently 31 . Thus, a systematic study of P, T -odd effects in molecules is of avail.…”

Diatomic molecules, a window onto fundamental physics

“…[5] Refs. [6][7][8] highlighted the particular situation of P, T -odd effects in the diatomic system RaF, which was earlier identified to have the advantage of being also a molecular candidate for laser-cooling. [9] Based on simple theoretical concepts [10] it was subsequently concluded that not only diatomic, but also polyatomic molecules can be cooled with lasers.…”

Calculation of hyperfine structure constants of small molecules using Z-vector method in the relativistic coupled-cluster framework

“…37 , we have shown that the Z-vector method can produce very good wavefunction in the nuclear region of moderately heavy molecules like SrF. Similarly, Z-vector method can also produce an accurate wavefunction in the nuclear region of heavy diatomic molecules [38][39][40] . So, altogether, we can say that the Z-vector is a very reliable method to produce high quality wavefunction in the core region.…”