THE VIBRATION-ROTATIONAL BANDS NU-3, 2-NU-3 - NU-3, AND NU-3 + NU-6 - NU-6 OF H3 (CF)C-12

The vibration-rotational bands ν3, 2ν3 - ν3, and ν3 + ν6 - ν6 of gaseous fluoromethane H312CF in the 10 μm region have been measured in absorption on an interferometric spectrometer with spectral resolution 0.002 cm-1. Simultaneously with 95 previously reported frequencies of pure rotational transitions in the ground vibrational state and 55 rotational transitions in the excited vibrational state v3 = 1, the wavenumbers of 1161 vibration-rotational transitions of the ν3 band and of 502 vibration-rotational transitions of the band 2ν3 - ν3 have been fitted to determine 14 parameters of the ν3 band and 13 parameters of the band 2ν3 - ν3 which describe the infrared data with a standard deviation 5.6 × 10-5 cm-1. For possible use as secondary standards for wavenumber calibration, 290 selected lines of the fundamental band are listed in the range 958-1097 cm-1. The wavenumbers of 614 lines of the "hot" band ν3 + ν6 - ν6 have been used to determine 15 parameters of this band which describe the experimental data with a standard deviation 7.6 × 10-5 cm-1. Opposite signs of the effective coefficients of the "2, 2" l-type interaction in the vibrational states ∥v3, ν6l〉 = ∥0, 1±1〉 and ∥1, 1±1〉 of H312CF have been explained by different coupling schemes for the x-y Coriolis interactions affecting the states ∥0, 1±1〉 and ∥1, 1±1〉. © 1991.