Fluorescence spectra and the rate of optical collisions

Abstract

The effect of binary collisions on the fluorescence spectrum of an atom in a nearly resonant monochromatic radiation fievd is evaluated in terms of formal relaxation and correlation operators that refer to a single collision. The driving field can be included in the atomic Hamiltonian, and its time dependence is transformed away, giving rise to a modified atom. The authors relate the strengths and the widths of line occurring in the fluorescence spectrum to the rate of optical collisions, and to other elements of the scattering matrix of the modified atom.