Inelastic and adiabatic contributions to atomic polarizability

Abstract
We show that it is not always possible to describe a vapor by a Doppler-free model when several beams create a grating inside the vapor. This result, which is even true in the nonresonant case, is due to inelastic processes (collision, spontaneous emission). We show that it can be important to separate the adiabatic and inelastic contributions to the atomic polarizability, which have different time constants.