The Coriolis Interaction between the v9 and v7 Fundamental Bands of Methylene Fluoride

Abstract

The infrared spectrum of the v7 and v9 bands of methylene fluoride-d2 (CD2F2) has been recorded with an unapodized resolution of 0.0024 cm-1 in the frequency range of 940-1030 cm-1 using the Fourier transform technique. A weak b-type Coriolis interaction term was found to couple these two vibrational states with band centers about 42 cm-1 apart. By fitting a total of 1031 infrared transitions of both v7 and v9 with a standard deviation of 0.0011 cm-1 using a Watson's A-reduced Hamiltonian in the Ir representation with the inclusion of a b-type Coriolis resonance term, two sets of rovibrational constants for v7 = 1 and v9 = 1 states up to sextic order were derived. The v7 band is C type, while the v9 band is A type with band centers at 961.8958 ± 0.0005 and 1003.7421 ± 0.0001 cm-1, respectively. © 2000 Academic Press.