Electroweak quantum chemistry for nuclear-magnetic-resonance-shielding constants: Impact of electron correlation

One promising route towards the first experimental verification of parity violation (PV) in chiral molecular systems is the detection of line splittings between nuclear magnetic resonance (NMR) spectra of enantiomers. Those numerical methods which can be systematically refined and allow for an accurate and reliable prediction of molecular PV effects will play a crucial role for the preparation and interpretation of such experiments. In this work the ab initio calculation of isotropic parity-violating NMR-shielding constants (sigma(PV)) within coupled cluster and multiconfiguration linear response approaches to electroweak quantum chemistry is reported and the results are compared to data obtained at the uncoupled density functional theory level. The sigma(PV) of the heavy nuclei in hydrogen peroxide, disulfane and diselane (H2X2 with X=O-17, S-33, Se-77) computed at the coupled cluster singles and doubles level are found to typically deviate from their electron-uncorrelated counterparts by approximately 20%, while in 2-fluorooxirane, electron correlation alters sigma(PV) of individual nuclei by almost a factor of 2. It is therefore imperative in the accurate prediction of parity-nonconserving phenomena in NMR experiments that systematically improvable electron-correlating electroweak quantum chemical approaches, such as those presented in this study, are employed.