We review the high-resolution spectroscopic approach toward the study of intramolecular dynamics, emphasizing molecular parity violation. Theoretical work in the past decade has shown that parity-violating potentials in chiral molecules are much larger (typically one to two orders of magnitude) than anticipated on the basis of older theories. This makes experimental approaches toward small molecular parity-violating effects promising. The concepts and results of intramolecular dynamics derived from spectroscopy are analyzed as a sequence of symmetry breakings. We summarize the concepts of symmetry breakings (de facto and de lege) in view of parity violation in chiral molecules. The experimental schemes and the current status of spectroscopic experiments on molecular parity violation are established. We discuss the promises of detecting and accurately measuring parity-violating energy differences Delta(pv) E on the order of 10(11) J mol(1) (approximately 100 aeV) in enantiomers of chiral molecules with regard to their contribution to fundamental physics in the framework of the standard model of particle physics and more speculative future fundamental symmetry tests such as for the combined charge conjugation, parity, and time-reversal (CPT) symmetry violation.

Bijvoet's method, which makes use of anomalous x-ray diffraction or dispersion, is the standard means of directly determining the absolute (stereochemical) configuration of molecules, but it requires crystalline samples and often proves challenging in structures exclusively comprising light atoms. Herein, we demonstrate a mass spectrometry approach that directly images the absolute configuration of individual molecules in the gas phase by cold target recoil ion momentum spectroscopy after laser ionization-induced Coulomb explosion. This technique is applied to the prototypical chiral molecule bromochlorofluoromethane and the isotopically chiral methane derivative bromodichloromethane.

We study the effect of parity violation on the vibrational and rotational frequencies of CHBrClF. We report the parity violating potentials as a function of reduced normal coordinates for all nine internal vibrational modes omega(1) to omega(9), using our new, accurate multiconfigurational-linear response (RPA and complete-active-space self-consistent field) approach. All modes omega(i) show a strongly mode dependent relative shift Delta(pv)omega(i)/omega(i) (between 0.08x10(-16) and 13.3x10(-16), much smaller than all previous experimental tests could detect, including the most recent ones). The results are discussed in relation to other tests of parity violation.

Parity violation causes rovibrational frequency shifts in infrared and microwave spectra between the corresponding lines of enantiomers of chiral molecules. In previous theoretical treatments of this effect simple harmonic and anharmonic adiabatic approximations were used which assumed that the vibrational potential as well as the parity violating potential are separable in normal (or local) coordinates. In the present work we investigate in detail the influence of nonseparable anharmonic couplings on vibrational frequency shifts caused by the parity violating potential in CDBrClF. We use the strongly coupled four-dimensional CD- and CF-chromophore subspaces and discuss how relative frequency shifts are influenced by coupling in the pure vibrational potential as well as in the parity violating potential. A four-dimensional parity violating potential energy hypersurface has been determined ab initio and fitted to a polynomial expansion. We analyze the nonseparable multidimensional representation of the parity violating potential in a chiral molecule. The effects of the multidimensional anharmonic couplings provide the dominant corrections. They are found to be about 20% for the expectation value of the parity violating energy difference ΔpvE between enantiomers (coupled ΔpvE/hc≈1.76×10−12 cm−1 compared to 1.96×10−12 cm−1 uncoupled). The corrections due to anharmonic multidimensional coupling can be more than a factor of 2 for vibrational frequency shifts, depending on the mode considered.