  In a recent work, we provided a standardized and exact analytical formalism
for computing in the semiclassical regime the radiation force experienced by a
two-level atom interacting with any number of plane waves with arbitrary
intensities, frequencies, phases, and propagation directions [J. Opt. Soc. Am.
B \textbf{35}, 127-132 (2018)]. Here, we extend this treatment to the
multilevel atom case, where degeneracy of the atomic levels is considered and
polarization of light enters into play. A matrix formalism is developed to this
aim.
