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High-resolution FTIR spectroscopy of the C—Cl stretching mode of vinyl chloride

1999; Taylor & Francis; Volume: 96; Issue: 1 Linguagem: Inglês

10.1080/00268979909482942

1362-3028

Alessandra De Lorenzi, S. Giorgianni, Roberto Bini,

Spectroscopy and Laser Applications

The vibration—rotation spectra of natural CH2=CHCl and mono-isotopic CH2=CH37Cl (isotopic purity, 95%) have been studied in the ν8 band region near 720 cm−1 with a resolution of 0.005 cm−1, by using a Fourier transform infrared spectrometer. This vibration of symmetry species A′ is expected to give rise to an a/b hybrid band with a predominant contribution of the a-type component. Both J and K structures have been resolved in different subbranches and the rovibrational analysis led to the assignment of about 3300 (J ⩽ 78, K a ⩽ 16) and more than 3000 (J ⩽ 79, K a ⩽ 16) transitions of 35Cl and 37Cl isotopomers, respectively. The P- and R-branch spectrum with high J values shows a series of lines arising from oblate-type near-degeneracy. Using Watson's A-reduction Hamiltonian in the Ir representation, a least-squares fit of the identified transitions provided excited state constants of the ν8 band for both the isotopic species, which turned out to be free from perturbations.