  Modifications in the spontaneous emission rate of an excited atom that are
caused by extinction effects in a nearby dielectric medium are analyzed in a
quantummechanical model, in which the medium consists of spherical scatterers
with absorptive properties. Use of the dyadic Green function of the
electromagnetic field near a a dielectric sphere leads to an expression for the
change in the emission rate as a series of multipole contributions for which
analytical formulas are obtained. The results for the modified emission rate as
a function of the distance between the excited atom and the dielectric medium
show the influence of both absorption and scattering processes.
