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 <math>n<math> is given by

<math>

 n \approx \sqrt{1 + \frac{3 A p}{R T}}

<math>

where <math>A<math> is the molar refractivity, <math>p<math> is the pressure of the gas, <math>R<math> is the universal gas constant, and <math>T<math> 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.