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 *n* is given by

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

Last updated: 05-07-2005 05:06:02

Last updated: 05-13-2005 07:56:04