Temperature dependence of the optical properties of liquid toluene between 4000 and 400 cm−1 from 30 to 105 °C

This paper presents the first systematic study of the temperature dependence of the optical properties of a liquid. The real and imaginary refractive index spectra, and imaginary molar polarizability spectra of toluene were determined from 30 to 105 °C in 5 °C increments. The peak positions, heights and widths all vary linearly with temperature. However, the broadening of the peak width and lowering of the height are in such a manner that the integrated intensities, transition moments and dipole moment derivatives remain constant. Points in the absorption spectra were observed to be independent of temperature. These points have been labeled isoentosic points.