			15min:

SYMMETRY-BASED TUNNELINGS IN HIGH-RESOLUTION ROVIBRATIONAL SPECTRA OF OCTAHEDRAL MOLECULES.

JUSTIN MITCHELL, WILLIAM HARTER, Department of Physics, University of Arkansas, Fayetteville, AR 72701.

High-resolution spectra of spherical-top molecules are known to demonstrate rotational level clustering. This clustering is well described as a rotational phase-space effect. Multiple equivalent phase-space regions allow tunneling and thus splitting of the rotational clusters. So far this has been done with an ad hoc tunneling Hamiltonian. Similar splittings have been shown for low dimensional systems, also with an ad hoc parameterization. While ad hoc tunneling parameterization is simple to understand, it becomes extremely difficult to apply for higher symmetries and for locally low-symmetry clustering when many tunneling paths are possible. Symmetry-based parameterization mitigates this complication.

This presentation will discuss how symmetry-based tunneling is applied for octahedral molecules and demonstrate how local-C₁, C₂ , C₃ or C₄ clusters may be evaluated perturbatively. Connections to non-rotational systems, such as large amplitude motion, will be discussed as well.