Refractive Index of Water and Its Dependence on Wavelength, Temperature, and Density

Abstract

A survey of the available experimental data and the existing equations for the refractive index of water is given. The dependence of the molar refraction on wavelength, temperature, and density is shown over an extended range. Based upon the electromagnetic theory of light an equation for the refractive index of water with wavelength, temperature, and density as independent variables is constructed. Its coefficients are directly deduced from all available experimental data by least squares fit. The range of validity of wavelength is restricted by the theory for normal dispersion to 182 nm≤λ≤2770 nm. The range of temperature and density is given by the available experimental data. Interpolations between the single measured points are possible and the following range of validity can be recommended: for temperature -10 °C≤T≤500 °C and for density 0.0028 kg/m3 ≤≤1045 kg/m3. Good agreement exists between the new relation, the available experimental data, and several existing equations. © 1985, American Institute of Physics for the National Institute of Standards and Technology. All rights reserved.