Vibrational and vibration-rotational spectroscopy of CBrClF2 (Halon-1211) Original Research Article

The infrared spectrum of Halon-1211, CBrClF2, in a supersonic jet expansion has been measured by high resolution FTIR spectroscopy and the rotational structure of the ν1 B-type band at 1100 cm−1 and the ν7 C-type band at 1151 cm−1 have been analyzed. Upper state rotational constants have been obtained for the C79Br35ClF2 and C81Br35ClF2 isotopomers, and these have been used to simulate the band structure, enabling the rotational temperature in the jet to be estimated at 40 K. In addition, low resolution far infrared and mid infrared spectra along with gas phase Raman spectra of CBrClF2 have been recorded at room temperature and the vibrational fundamentals more completely assigned. These results are compared with the values predicted by molecular orbital calculations at the LANL1DZ, 6-311G∗∗ and MP26-311G∗∗ levels of theory.