15min:

D. MURDOCK, L. A. BURNS AND P. H. VACCARO, Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107.

The mode specificity of proton-transfer dynamics in the ground state (X ¹ \textrmA₁) of tropolone has been explored at near-rotational resolution by implementing a fully coherent variant of stimulated emission pumping within the framework of two-color resonant four-wave mixing spectroscopy (TC-RFWM). Ongoing studies have exploited rovibronically-resolved features of the A-X origin band as a ``doorway'' for selectively interrogating vibrationally-excited levels of the ground electronic manifold, with judicious selection of incident/detected polarization characteristics affording a means for discriminating rotational branches and alleviating spectral congestion.\footnoteA.~E.~Bracamonte and P.~H.~Vaccaro, J. Chem. Phys. \textbf119(2), 887 (2003); \textbf120(10), 4638 (2004). Several mid-range vibrational transitions (E_vib\leq1700 cm^-1) have been interrogated under ambient, bulk-gas conditions, with term energies determined for the symmetric and antisymmetric (tunneling) components enabling the attendant tunneling-induced bifurcations to be extracted. The dependence of tunneling rate (or hydron migration efficiency) on vibrational motion is discussed in terms of corresponding atomic displacements and permutation-inversion symmetries for the tropolone skeleton.