Ab initio calculation of parity‐violating potential energy hypersurfaces of chiral molecules Dedicated to Hans Bürger on the occasion of his 65th birthday.

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 H2O2 and H2S2 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 (Epv) with increasing bond lengths rOO and rSS, 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 Epv at chiral geometries, and the absence of a precise, simple scaling law for observables such as the measurable parity‐violating energy difference between enantiomers ΔEpv. The latter is due to the complicated geometry dependent Epv, 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. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 [ABSTRACT FROM AUTHOR]