Absolute integrated infrared intensities of liquid fluorobenzene between 4000 and 400 cm at 25 °C

This paper is a continuation of the study of the integrated absorption intensities of benzene and its simple derivatives. In this paper, the imaginary molar polarizability spectrum reported earlier for fluorobenzene was fit with 169 classical damped harmonic oscillator bands. The standard deviation and RMSE of the fit are both 0.006 cm³ mol⁻¹and the area under the fitted spectrum is 0.5% larger than the area under the experimental spectrum. Most of the required peaks are assigned to fundamentals, first overtones or binary combinations. From the parameters of the fitted peaks, the integrated intensities, transition moments and dipole moment derivatives with respect to normal coordinates of the infrared active fundamentals are determined. The F-Sum rule is used to compare the integrated intensities to those of benzene and bromobenzene in the literature. Remarkably, the F-Sums of the out-of-plane vibrations are the same in all the molecules while the in-plane F-Sums vary markedly between the different molecules.