High-Resolution Infrared Spectrum and Analysis of the v2 Band of CF3Br

The vibrorotational spectrum of CF,Br in natural isotopic abundance has been recorded in the 747 to 775 cm-' region using a tunable diode laser spectrometer. The K-structure of both isotopic varieties (CF,79Br and CFj8'Br) could be resolved for a series of P(J) and R(J) multiplets. Accurate molecular constants were determined from a least-squares fit of the observed transition frequencies. This fit yielded band origins of the v2 vibration of 762.1499( 5) cm-' (76 1.95 13( 5 ) cm-') and values of oI$ of 139.9( 15) X 1O-6 cm-' (138.8( 17) X 10m6 cm-') and &of 70.0(3) X 10s6 cm-' (68.0( 3) X 10e6 cm-') for CF979Br and CFx8'Br, respectively.