The density of excited atoms and the diffusely reemitted radiation is calculated for a homogeneous radiation field incident on a slab. The solutions of the Biberman-Holstein integral equation are used in the calculations. The optical thickness is assumed to be large. The line shapes of both the absorption line and the incident radiation are arbitrary.

• Received 19 April 1971

DOI:https://doi.org/10.1103/PhysRevA.4.1303