Absolute absorption intensities in the fundamental v₂ and v₅ bands of ¹²CH₃F

The absolute strengths of 93 lines belonging to the v and v bands of methyl fluoride were measured in the range of 1416-1503 cm using a tunable diode-laser (TDL) spectrometer. These experimental line intensities were obtained from the equivalent width method. The intensities were analyzed within a dyad system, required to account properly for the strong Coriolis coupling between v and v . The fit to the experimental data led to the determination of the dipole moment derivatives ∂μ/∂q and ∂μ/∂q , as well as the first-order Herman-Wallis correction in K to ∂μ/∂q . The intensities were reproduced with an overall standard deviation of 1.44%, to be compared with a mean experimental uncertainty equal to 1.58%. The values derived for the vibrational band strengths of v and v are 2.124 (18) cm · atm and 36.96 (12) cm · atm at 296 K, respectively,