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Release on the Refractive Index of Ordinary Water substance as a Function of Wavelength, Temperature and Pressure
September 1997

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This formulation is recommended for the calculation of the refractive index of ordinary water as a function of temperature, density, and wavelength up to 500 °C and 1060 kg m−3. The range of wavelengths covered is 0.2-1.1 μm, and extrapolation is reasonable up to 1.9 μm. It is valid in the stable fluid range up to these limits, and also for the supercooled liquid down to −12 °C.
The development of the formulation and comparisons to available data are described in detail in a scientific article and references therein.

Revision History

This Release is the product of the Working Group "Thermophysical Properties of Water and Steam" (TPWS) of the International Association for the Properties of Water and Steam (IAPWS).

This page updated June 7, 2018

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