High-resolution infrared spectrum of CHD279Br: ro-vibrational analysis of the ν5 and ν9 fundamentals

The high-resolution infrared spectrum of (CHD2Br)-Br-79 has been investigated by Fourier transform spectroscopy in the range 700-900 cm(-1) at an unapodized resolution of 0.0035 cm(-1). This spectral region is characterised by the absorptions of the nu(5) (814.5185 cm(-1)) and nu(9) (716.9649 cm(-1)) fundamental bands, corresponding to H-C-Br deformation and CD2 rocking modes, respectively. The nu(5) vibration of symmetry species A(') gives rise to an a-/c-hybrid band with a predominant a-type component, while the nu(9) mode of A('') symmetry produces a b-type envelope. The spectral analysis resulted in the identification of 5290 (J(') <= 63 and K-a(') <= 13) and 1657 (J(') <= 53 and K-a(') <= 12) transitions for nu(5) and nu(9) bands, respectively. The assigned data were fitted using the Watson's S-reduced Hamiltonian in the I (R) representation and the v(5) = 1 and v(9) = 1 state parameters up to the quartic centrifugal distortion terms have been obtained. From spectral simulations the dipole moment ratio |Delta mu(a)/Delta mu(c)| of the nu(5) band has been determined to be 1.4 +/- 0.1 while the intensity ratio between nu(5) and nu(9) fundamentals has been estimated to have a value of 4.3 +/- 0.5.