  We consider combined stimulated Raman adiabatic passage (STIRAP) and fast
forward field (FFF) control of selective vibrational population transfer in a
polyatomic molecule. The motivation for using this combination control scheme
is twofold: (i) to overcome transfer inefficiency that occurs when the STIRAP
fields and pulse durations must be restricted to avoid excitation of population
transfers that compete with the targeted transfer and (ii) to overcome transfer
inefficiency resulting from embedding of the actively driven subset of states
in a large manifold of states. We show that, in a subset of states that is
coupled to background states, a combination of STIRAP and FFFs that do not
individually generate processes that are competitive with the desired
population transfer can generate greater population transfer efficiency than
can ordinary STIRAP with similar field strength and/or pulse duration. The
vehicle for our considerations is enhancing the yield of HNC in the driven
ground state-to-ground state nonrotating HCN/HNC isomerization reaction and
selective population of one of a pair of near degenerate states in non rotating
SCCl$_2$.
