Resonant Scattering of Monochromatic Light in Gases

Abstract

The resonant scattering of monochromatic light in gases is analyzed. Explicit expressions for the differential cross section are obtained in the limits (Doppler width) ≫ (natural width) ≫ (collision width) and (collision width) ≫ (natural width) ≫ (Doppler width). In the former limit, the frequency distribution of scattered light is narrowed in the forward and backward directions, and has the full absorption width for right-angle scattering. In the collision-dominated limit, the cross section separates into a coherent and a fluorescent component. The motion of the atoms broadens the $\delta$ function distribution characterizing coherent scattering from a stationary target. The interference between light scattered by different atoms is assessed.