ANOMALOUS ASYMMETRY SPLITTINGS IN A MOLECULE WITH INTERNAL-ROTATION IN THE PRESENCE OF CLASSICAL CHAOS

Rotation-torsion energy levels of acetaldehyde calculated from a spect roscopic Hamiltonian obtained from the fit of high-resolution microwav e and far-infrared spectra, exhibit anomalously large Splittings for s ome asymmetry doublets. It is shown that these anomalies are caused by chaos-enhanced quantum dynamical tunnelling between classically disco nnected regions of the phase space. A major consequence of this phenom enon is the magnification of intramolecular energy-transfer processes.