Ab Initio Calculation of Parity-Violating Potential Energy Hypersurfaces of Chiral Molecules

摘要

We introduce the explicit concept of parity-violating potential energy hypersurfaces which govern the rotation-vibration tunneling dynamics as well as the time-dependent parity violation in chiral molecules.Calculations are reported for sections of the hypersurfaces of H_2O_2 and H_2S_2 at various levels of electroweak quantum chemistry,including CIS-RHF,CIS-LR,and CASSCF-LR.Important findings concern the observed increase of the parity-violating potentials(E_pv)with increasing bond lengths r_(indent)and r_ss,which is to some extent physical and partly a consequence of the only approximate electronic wavefunction and perturbational treatment,the confirmation of lines and surfaces of "accidentally" zero E_pv at chiral geometries,and the absence of a precise,simple scaling law for observables such as the measurable parity-violating energy difference between enantiomers AE_pv.The latter is due to the complicated geometry dependent E_pv,although a rough scaling on the order of Z~(5(+-)1)with nuclear charges of the two heavy centers can be confirmed.The results are discussed in relation to possible experiments on molecular parity violation.