An infrared laser sideband spectrometer operating in the CO2 laser region with 8- to 18-GHz sidebands has been used to record 266 transitions in the ν3 band and 84 transitions in the 2ν3 ← ν3 band of 12CH3F. The accuracy of the measured frequencies is estimated to be 1-3 MHz. A millimeter/submillimeter-wave spectrometer has been used to record the spectra of 48 pure rotational transitions in the ground vibrational state and 55 transitions in the v3 = 1 vibrational state with an accuracy of 20-90 kHz. The new measurements have been combined with previous radio frequency and infrared laser results to derive sets of constants for the ground, v3 = 1, and v3 = 2 states for this molecule. Tables of the vibrational dependence of the parameters and of the near coincidences of the ν3 and 2ν3 ← ν3 band transitions with CO2 laser frequencies are given.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry