A method for determination of the refractive index in a region of absorption. Anomalous dispersion of CS 2 in the UV range

Abstract

A method is described for determining the refractive index of, e.g., a liquid solution, within an absorption band by studying the linear dichroism generated by different reflections at inclined optical incidence. The method requires a sensitive differential photometric technique, such as that accomplished in a circular dichroism spectrometer. The refractive index of CS 2 is reported in the region 260–450 mm. and the result compared to that obtained from a Kramers-Kronig integration on the 320 nm absorption band. Though this band is fairly isolated the experimentally gained result was found more reliable. This was due to difficulties in obtaining an accurate absorption coefficient of liquid CS 2 as well as to the fact that the integration had to be restricted to a finite spectral range.