To achieve large population transfer to high vibrational levels in a selected ground-state mode of a polyatomic molecule [Cr(CO)(6)], we apply chirped femtosecond mid-infrared laser pulses at 2000 cm(-1) to optimize vibrational ladder climbing as an energy deposition mechanism, which in turn controls the outcome of a unimolecular dissociation process. Its dependence on excitation parameters (frequency, intensity, chirp) is investigated and found to be in excellent agreement with a theoretical calculation. In particular, it is shown that optimizing vibrational ladder climbing allows for coherently controlled excitation even in a polyatomic molecule. (C) 2003 American Institute of Physics.