Measurement of refractive indices of binary mixtures using digital interferometry and multi-wavelength Abbemat refractometer

Refractive index is one of the most important physical properties of transparent solid, liquid and gas. Accurate knowledge of refractive index is highly relevant to correlate with concentration, temperature, wavelength and pressure in non-intrusive experiments carried in transparent fluids. It can be used for the identification and characterization of pure materials, for the measurement of concentration of multi-component mixtures etc. In this current scope, refractive indices of five binary mixtures decane (C10H22)-isobutylbenzene (IBB), decane (C10H22)-1,2,3,4tetrahydronaphthalene (THN), dodecane (C12H26)-isobutylbenzene (IBB), dodecane (C12H26)-1,2,3,4tetrahydronaphthalene (THN) and isobutylbenzene (IBB)-1,2,3,4tetrahydronaphthalene (THN) have been measured using both Mach-Zehnder interferometer and a multi-wavelength Abbemat refractometer. Temperature and concentration coefficient of refractive indices or so called contrast factors as well as their individual correlation to calculate refractive indices have been presented for wide range of visible spectrum i.e., 436 nm to 657 nm. Comparison with available literature data and mixing rules shows that new correlation can predict the experimental data with some acceptable error.