THE LORENTZ LOCAL-FIELD IN NONLINEAR DIELECTRICS

An expression of the Clausius-Mossotti type is derived for the macrosc opic electric polarization in a medium of nonlinear polarizable point dipoles, following the method proposed by Lorentz. The polarizing mech anism is assumed to have arbitrary nonlinear character, and no assumpt ion on the strength of the electric field is made. As an application, a medium of two-level atoms, submitted to a harmonic electric field, i s considered. For this case, the magnitude of the locaI field effects is investigated by comparison of the dipole moment per atom as calcula ted from the Clausius-Mossotti-type expression for a dense medium with that of an isolated atom.