  The theory of rovibronic spectroscopy of light-dressed molecules is presented
within the framework of quantum mechanically treated molecules interacting with
classical light fields. Numerical applications are demonstrated for the
homonuclear diatomic molecule Na$_2$, for which the general formulae can be
simplified considerably and the physical processes leading to the light-dressed
spectra can be understood straightforwardly. The physical origin of different
peaks in the light-dressed spectrum of Na$_2$ is given and the light-dressed
spectrum is investigated in terms of its dependence on the dressing field's
intensity and wavelength, the turn-on time of the dressing field, and the
temperature. The important implications of light-dressed spectroscopy on
deriving field-free spectroscopic quantities are also discussed.
