On the role of coupling in mode selective excitation using ultrafast   pulse shaping in stimulated Raman spectroscopy
  The coherence of two, coupled two-level systems, representing vibrational modes in a semiclassical model, is calculated in weak and strong fields for various coupling schemes and for different relative phases between initial state amplitudes. A relative phase equal to $\pi$ projects the system into a dark state. The selective excitation of one of the two, two-level systems is studied as a function of coupling strength and initial phases. 
S.A. Malinovskaya, P.H. Bucksbaum, and P.R. Berman