Spectroscopic constants of the ground and lower vibrational states of CH281BrF: A combined high resolution infrared and microwave study

The enriched 81Br isotopic species of bromofluoromethane has been investigated in the infrared and microwave regions. The rovibrational spectrum of the ν5 fundamental has been studied by high resolution FTIR spectroscopy, while the rotational spectra of the ground and v6 = 1 states have been observed by means of microwave spectroscopy. More than 2700 transitions have been assigned in the ν5 band and the analysis of the rovibrational structure reveals a first-order c-type Coriolis resonance with the v6 = 2 state. The present study improves the ground state constants available in the literature and enables the determination of further centrifugal distortion parameters together with the full bromine quadrupole coupling tensor. A set of spectroscopic parameters up to the sextic distortion terms for the vibrational excited states has been accurately evaluated for the first time.