Quantum control spectroscopy of vibrational modes:: Comparison of control scenarios for ground and excited states in β-carotene

Quantum control spectroscopy (QCS) is used as a tool to study, address selectively and enhance vibrational wavepacket motion in large solvated molecules. By contrasting the application of Fourier-limited and phase-modulated excitation on different electronic states, the interplay between the controllability of vibrational coherence and electronic resonance is revealed. We contrast control on electronic ground and excited state by introducing an additional pump beam prior to a DFWM-sequence (Pump-DFWM). Via phase modulation of this initial pump pulse, coherent control is extended to structural evolution on the vibrationally hot ground state (hot-SO) and lowest lying excited state (S-1) of beta-carotene. In an open loop setup, the control scenarios for these different electronic states are compared in their effectiveness and mechanism. (C) 2008 Elsevier B.V. All rights reserved.