Impact of the nuclear model and electron correlation on the parity-violation effects on the electric field gradient

Abstract

In this work, the parity violation (PV) effects on the electric field gradient (EFG) at a four-component (4c) Density Functional Theory (DFT) level are presented. Such effects were studied previously [J. J. Aucar and A. F. Maldonado, Phys. Chem. Chem. Phys. 27, 7594 (2025)] at the Dirac–Hartree–Fock level in several chiral molecules. In the present study, we include electron-correlation effects at the DFT level with the PBE0 functional, as it was shown to give a good performance in the parity conserving (PC) part of the EFG as well as in the PC nuclear quadrupole coupling constant calculations. We study the basis-set convergence on the PV effects on EFG, improving the core region and adding s- and p-type tight functions to the nuclei under consideration. Finally, we also analyze nuclear-model effects, including a more realistic charge distribution of the nuclei under study through a relativistic point-coupling energy model, denoted as the DD-PCX nuclear model, and compare it with the widely used Gaussian charge distribution model. All these corrections improve the accuracy of calculations. Nuclear-model effects were found to be significant also for the PV effects in energy, and their impact must be studied for PV effects in other properties.