DIODE-LASER SPECTROSCOPY OF THE NU-6 BAND OF METHYL-FLUORIDE

The five Q branches, PQ1, RQ0, RQ1, RQ2, and RQ3, of the ν6 band of methyl fluoride 12CH3F were observed by using a tunable diode laser spectrometer and were analyzed to obtain the following molecular constants (in cm-1): ν ̃6 = 1182.67605(80), A6 = 5.2006(14), (Aζ)6 = 1.5437(11), and (Aζ)6ηK = 1.6(11) × 10-4, with 2.5 times the standard errors in parentheses. The precision of the band origin may, however, be 0.001-0.002 cm-1 because of the wavelength uncertainties of the N2O spectral lines used as the references. An analysis of the RQ0 subband determined the sign of the q6 constant to be positive. The α6A, α6B, and q6 constants of methyl fluoride are discussed in terms of the anharmonic potential field. © 1979.