Measurement of optical contrast factors in ternary hydrocarbon mixtures

Abstract

Deriving the refraction index over temperature and concentration is essential in thermal diffusion measurements. In the present study, we attempt to provide precise experimental measurements of the optical contrast factors of two ternary systems formed by three hydrocarbon components – 1,2,3,4-tetrahydronaphtalene (THN), isobutylbenzene (IBB), and n-dodecane. For each system we consider three different contrast factors: , and . The mixtures were prepared and investigated using a wide range of temperatures and wavelengths. The refractive index was measured using both the Mach–Zehnder Interferometer (MZI) and the multi-wavelength Abbemat Refractometer. A new development of the MZI cell holder used in the literature to measure contrast factors was presented and tested on ternary mixtures. In addition, this study compared the values of the experimental measurements of the refractive indices with theoretically estimated values using the mixing rules. The experimental values were in substantial agreement with all of the predictive values with the exception of the Oster (O) and Newton (N) equations.

Keywords:

• Refractive index
• ternary mixture
• contrast factor
• refractometry
• interferometry

Additional information

Funding

We acknowledge the financial support of Canadian Space Agency (CSA) for this work.