High-resolution fourier transform infrared spectroscopy of vinyl alcohol: Rotational analysis of the nu(13) CH2 wagging fundamental at 817 cm(-1)

The first high-resolution infrared spectra of the unstable molecule vinyl alcohol are reported. The spectra have been obtained using a new precursor, 2-chloroethanol, which when pyrolyzed at 1050 degrees C gives strong infrared spectra of vinyl alcohol free of interfering hydrocarbon absorption bands. In this work, we have analyzed the strong v(13) fundamental at 817 cm(-1) and substantially improved the ground state rotational constants by a simultaneous fitting of previous microwave data and a large number of infrared combination differences. The 13(1) upper state was found to be perturbed by the 15(2) "dark" state at 775.7 cm(-1), and a complete analysis of the perturbed rotational structure has been achieved using an interacting two-state model. Further small perturbations at high K-a, and J have been identified as interactions with the v(10) and v(12) fundamentals at 948 and 960 cm(-1), respectively. (C) 1999 Academic Press.