15min:
ROVIBRONIC ENERGY TOPOGRAPHY I: TENSOR EIGENVALUE STRUCTURE AND TUNNELING EFFECTS IN LOW-SYMMETRY SPECIES-CLUSTERS OF HIGH SYMMETRY MOLECULES.

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

Centrifugal and Coriolis effects on rovibrational eigensolutions may be analyzed and approximated by rotational-energy-surfaces (RES). This technique is extended to study high rank tensor Hamiltonians that model spectra of symmetric molecules such as CH4, SF6 and C60.

Of particular interest here is superfine structure, which was first studied with a fourth order rotational Hamiltonian and experimentally confirmed for SF6 and CH4. The theoretical framework for this study is reviewed for higher angular momentum and higher order Hamiltonians. Earlier studies show symmetry reduction into clusters of local C4 and C3 symmetry. Here we study effects of combinations of fourth, sixth and higher rank tensor Hamiltonians to investigate a reduction to C2 and C1 (no symmetry) clusters that involve tunneling between 12 or 24 equivalent local phase-space regions. An understanding of this low symmetry tunneling may prove useful in analysis of internal rotations and provide examples of monodromy.