Infrared Intensities of Liquids XIV: Accurate Optical Constants and Molar Absorption Coefficients between 4800 and 450 cm −1 of Chlorobenzene at 25°C from Spectra Recorded in Several Laboratories

Abstract

Accurate infrared absorption intensities of liquid chlorobenzene at 25°C are presented. Their accuracy was estimated from the agreement between the intensities measured by different spectroscopists using different instruments in different laboratories and by different spectroscopists using the same instrument in the same laboratory. The spectra from different spectroscopists have been averaged, unweighted, to give intensity spectra of chlorobenzene that are presented as the best available. The results are presented as graphs and tables of the molar absorption coefficient, E_m(ν˜), and the real and imaginary refractive indices, n(ν˜) and k(ν˜), between 4800 and 450 cm⁻¹. The peak heights and the areas under the bands in the absorption index (imaginary refractive index) spectrum are reported, as are areas under the molar absorption coefficient spectrum. Absorption index, k(ν˜), and molar absorption coefficient, E_m(ν˜), values are believed accurate to an average ±2.4% at the peaks of bands with k_max > 0.002 and ±3.3% at the peaks of bands with k_max < 0.002. In the baseline k(ν˜) is accurate to ∼ ±5% above 3000 cm⁻¹ and ∼ ±2.5% below 3000 cm⁻¹. The areas under bands in k(ν˜) and E_m(ν˜) spectra for which k_max > 0.002 are accurate to ±1.3% on average. The real refractive index, n(ν˜), values are believed to be accurate to ±0.2%.