  The small cross section of Raman scattering poses a great challenge for its
direct study at the single-molecule level. By exploiting the high Franck-Condon
factor of a common-mode resonance, choosing a large vibrational frequency
difference in electronic ground and excited states and operation at T < 2K, we
succeed at driving a coherent stimulated Raman transition in individual
molecules. We observe and model a spectral splitting that serves as a
characteristic signature of the phenomenon at hand. Our study sets the ground
for exploiting the intrinsic optomechanical degrees of freedom of molecules for
applications in solid-state quantum optics and information processing.
