High-Resolution FTIR Spectrum of CF 2CH 2 near 3060 cm −1: Rovibrational Analysis of the Methylene Symmetrical Stretching

Abstract

The infrared spectrum of CF 2CH 2 has been investigated in the CH 2 symmetric stretching region near 3060 cm −1 at a resolution of about 0.004 cm −1 using a Fourier transform infrared spectrometer. The analyzed ν 1 fundamental of symmetry species A 1 gives rise to an a-type band reflecting characteristics typical of molecules approaching to the oblate symmetric top limit. The band was found to be affected by different Coriolis-type resonances, and several states such as ν 2 + ν 8, 2ν 8 + ν 10, ν 8 + ν 9 + ν 11, and ν 2 + ν 5 + ν 11 seem to be involved in the interactions. The rovibrational analysis led to the identification of about 1700 lines in the P, Q, and R branches with J, K a , and K c values up to 59, 20, and 59, respectively. Transitions free of major resonance contributions were fitted using the Watson′s A-reduction Hamiltonian in the I r representation; a least-squares fit of about 1000 lines yielded a set of effective constants for the v 1 = 1 state of CF 2CH 2.