Infrared intensities of methyl fluoride: Determination of the signs of the dipole moment derivatives

Since the problem was presented by Abbate and Gussoni, resolution of the confusion on the infrared intensities of methyl fluoride has been hoped for. In the present study, the experimental data reported so far on this subject have been reinvestigated to find finally that the intensity value reported on the ν6 band of the CD3F molecule was very much in error and therefore caused essentially the present problem. By using the new data, an intensity analysis has been carried out again, and a unique set of solutions for the infrared intensity parameters has been determined for this molecule. The resulting parameter values are found to be in perfect accord with what chemical intuition predicts them to be.