Frankfurt 2006 – scientific programme
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MO: Molekülphysik
MO 28: Poster: Quantum Control
MO 28.7: Poster
Tuesday, March 14, 2006, 16:30–18:30, Labsaal
Quantum control spectroscopy in biomolecules — •Tiago Buckup, Wendel Wohlleben, Timo Lebold, Alexander Weigel, and Marcus Motzkus — Physikalische Chemie, Phillips Universität Marburg, 35043 Marburg, Germany
Biomolecules present very often complex energy deactivation networks with overlapping electronic absorption bands, which makes their study a difficult task. This can be specially true in transient absorption spectroscopy. However, quantum control techniques can be used to discriminate specific electronic states of interest by optimizing one, two or more photon transitions. Recently, we have shown the control of energy flow in the bacterial light-harvesting using shaped pump pulses in the visible and the selective population of different pathways in β-carotene using an additional depletion pulse in the transient absorption technique. Here, we make one step further and apply a closed-loop optimization setup to a prototype molecule (β-carotene) using a spatial light modulator to decipher the energy flow network after a multiphoton excitation with a ultrashort pulse in the near-IR. After excitation, two overlapping bands were detected and identified as the S1 state and the first triplet state T1. Using as feedback the transient absorption signal at a specific probe delay, the triplet signal could be optimized over the singlet contribution.