A G1 study of the isomers of ClOOBr and related systems

Stereomutation Tunneling Switching Dynamics and Parity Violation in Chlorineperoxide Cl−O−O−Cl

In a search for efficient spectroscopic avenues toward experiments on molecular parity violation, we investigate the stereomutation tunneling processes in the axially chiral chlorine isotopomers of Cl2O2 by the quasi-adiabatic channel reaction path Hamiltonian (RPH) approach and the corresponding parity violating potentials by means of quantum chemical calculations including our recently developed Multiconfiguration linear response (MC-LR) approach to electroweak quantum chemistry. The calculated ground-state torsional tunneling splittings for all isotopomers of Cl2O2 are much smaller than the parity violating energy differences Delta(pv)E between the enantiomers of these molecules and therefore parity violation is predicted to dominate the quantum dynamics of stereomutation at low energies. We also compare these with torsional ground-state tunneling splittings and parity violating energy differences of the whole series of axially chiral HXYH(+) isotopomers (with X, Y= Cl(+), O, S, Se, Te). A comparison with our previous results for the homologous molecule Cl2S2 shows that for Cl2O2 a spectroscopic high-resolution analysis should be easier and the energy region of large tunneling splittings should be more easily accessible by IR excitation. We thus propose a scheme using "tunneling switching" with vibrational excitation in order to carry out the measurement of time-dependent parity violation in superposition states of initially well-defined parity. We discuss the advantages and drawbacks of such an experiment that can be carried out entirely in the IR spectral range (for Cl2O2 or related molecules).

Quasiclassical trajectory studies on the gas-phase BrO self-reaction

The effect of initial vibrational energy and the mode of disposal of available energy into products for the disproportionation reaction between BrO radicals are studied using the quasiclassical trajectory (QCT) technique. The calculations are performed on an analytical potential enegy surface based on ab initio results reported for the three isomeric forms of (BrO)2 system. The results indicate a mild dependence on reactant vibrational energy, which is discussed in terms of the mechanistic aspects of the reaction. The study of the distribution of total accessible energy among products indicates a different mode of energy disposal in each path and hence important differences on the mechanism by which each channel takes place.