RICHARD L. REDINGTON AND THERESA E. REDINGTON, Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409; ROBERT L. SAMS, Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352.
Fourier transform infrared spectra including resolved spectral doublets for many transitions are reported for gaseous tropolone(OH), tropolone(OD), and (18-O,18-O)tropolone(OH) in the 800 to 150 cm-1 spectral range. The known zero-point tunneling splitting values 0 = 0.974 cm-1 for tropolone(OH) (Tanaka et al.) and 0.051 cm-1 for tropolone(OD) (Keske et al.) allow vibrational state-specific tunneling splittings v to be estimated for fundamentals including the three with the strongest OO stretching displacements [cf. for tropolone(OH) 13 = 435.22 cm-1 with 13 = 1.71 cm-1 = 1.76 0, and for tropolone(OD) 13 = 429.631 cm-1 with 13 = 0.311 cm-1 = 6.10 0]. In addition to revealing isotope-dependent v splittings the FTIR study demonstrates effects due to dynamic couplings and potential function anharmonicity. Vibrational reassignments are fostered and the pattern of v tunneling splitting values is interpreted to underscore the intrinsic multidimensionality of the tautomerization process in this nonrigid 15 atom molecule.