Refractive Index and Lorentz—Lorenz Function for Saturated Argon, Methane, and Carbon Tetrafluoride

Abstract

By means of the principle of minimum deviation, the refractive index was determined for argon, methane, and carbon tetrafluoride as saturated liquids from the triple point to the critical point. For argon, some measurements were also made on the saturated gas. For argon and methane, known values of the densities were used to compute the Lorentz—Lorenz function over the entire range of the saturation curve. For carbon tetrafluoride these computations were made only up to 0.7 of the critical temperature due to the lack of density data at higher values. The Lorentz—Lorenz function varies little with density and temperature for the three liquid phases. The argon measurements indicate definite increases in the Lorentz—Lorenz function on isothermal condensation.