Departure of emission profile ψ(x, τ) from CFR for the case of scattering on a two-level atom with radiatively broadened upper level. Different lines correspond to ψ(x,τ)/φ(x) at different line-center optical depths within the atmosphere (indicated in the figure legend). For comparison ψ(x, τ = 1)/φ(x), corresponding to scattering on a two-level atom with infinitely sharp upper and lower levels (namely CS in the atomic frame), is shown as a dashed line.