Overlapping resonances in the coherent control of radiationless transitions: Internal conversion in pyrazine

Coherent control of radiationless transitions is developed and applied to internal conversion. Conditions for active versus passive control are described and overlapping resonances are shown necessary for the phase control of radiationless transitions in molecular systems. Applications to pyrazine show the possibility of extensive control via optimized state preparation, as well as the significant role of overlapping resonances, even in the evolution of single vibrational states in S-2. (C) 2005 American Institute of Physics.