The high-resolution (0.0030 cm1) Fourier transform infrared spectrum of CH279BrF has been studied in part of the atmospheric window between 910 and 980 cm1, the region of the m9 (935.847 cm1) and m5 + m6 (961.239 cm1) bands. The m9 fundamental consists of a pseudo a-type band induced by Coriolis coupling with m5 + m6, in turn exhibiting a predominant a-type structure. Several interactions connecting these levels and the dark state 3m6 have been assessed. The whole data set is treated using Watson’s Areduced Hamiltonian in the Ir representation implemented with first order a- and b- and c-type Coriolis terms. A detailed analysis of the rotational structure yields a set of accurate upper-state parameters up to quartic distortion terms for m9 and m5 + m6. In addition, spectroscopic information about the dark ternary overtone of m6 has been obtained.
- High-resolution FTIR spectroscopy
- Molecular constants
- Coriolis interactions