A strong interaction between torsion and vibration in S and Sm-fluorotoluene.

We report results of a two dimensional laser induced fluorescence study of torsional states, low frequency vibrations, and combinations of torsion with low frequency vibration in m-fluorotoluene up to 560 cm in S and 350 cm in S. Evidence is presented for interactions between torsion and low frequency vibrations in both S and S, demonstrating that the coupling of torsion and vibration observed previously in toluene and p-fluorotoluene extends to a molecule with a threefold torsional barrier. This barrier is low in S (20 cm) and modest in S (116 cm).

Pervasive interactions between methyl torsion and low frequency vibrations in S and S-fluorotoluene.

We report two dimensional laser induced fluorescence spectral images exploring the lower torsion-vibration manifolds in S ( < 560 cm) and S ( < 420 cm) -fluorotoluene. Analysis of the images reveals strong torsion-vibration interactions and provides an extensive set of torsion-vibration state energies in both electronic states (estimated uncertainty ±0.2 cm), which are fit to determine key constants including barrier heights, torsional constants, and torsion-vibration interaction constants.