Lorentz-Lorenz

The Lorentz-Lorenz formula, also known as the Clausius-Mossotti equation and the Maxwell equation, relates the refractive index of a dilute gas to its temperature, pressure, and molar refractivity. The index of refraction is given by

where is the molar refractivity, is the pressure of the gas, is the universal gas constant, and is the (absolute) temperature.

History

The Lorentz-Lorenz formula is named after the Danish mathematician and scientist Ludwig Valentine Lorenz, who published it in 1869, and the Dutch physicist Hendrik Lorentz, who discovered it independently in 1870.