  Effects of coupling between a molecular exciton and a surface plasmon
(exciton-plasmon coupling) on the luminescence properties of the molecule and
the surface plasmons are investigated using the nonequilibrium Green's function
method. Molecular absorption and enhancement by molecular electronic and
vibrational modes (molecular modes) lead to dip and peak structures in the
luminescence spectra of the surface plasmons. These structures will correspond
to the peak and dip structures observed in a recent experiment. We found that
in addition to the molecular dynamics, the re-absorption by the surface
plasmons plays important roles in determining the luminescence spectral
profiles.
