PNNL

Abstract

The 2-d1 and 3-d1 isotopologues of trans-hexatriene have been synthesized, and their high-resolution (0.0015 cm-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 anharmonic wavenumbers and harmonic intensities have been computed and compared with experiment where possible.