Analysis of the Rotational Structure in the High-Resolution Infrared Spectra of Trans-Hexatriene-2-D(1) And-3-D(1)

The 2-d1 and 3-d1 isotopologues of trans-hexatriene have been synthesized, and their high-resolution (0.0015cm−1) IR spectra have been recorded. For each of the isotopologues the rotational structure in four C-type bands for out-of-plane vibrational modes has been analyzed, and the ground state combination differences (GSCDs) have been pooled. Ground state rotational constants have been fitted to the GSCDs. For the 2-d species, A0, B0, and C0 values of 0.7837254(5), 0.0442806(3), and 0.0419299(2)cm−1 were fitted to 2450 GSCDs. For the 3-d species, A0, B0, and C0 values of 0.7952226(8), 0.0446149(7), and 0.0422661(4)cm−1 were fitted to 2234 GSCDs. For the eleven out-of-plane modes of the two isotopologues, predictions of wavenumbers corrected for anharmonicity and harmonic intensities have been computed and compared with experiment where possible.