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Ultrafast EUV probe for Molecular Reaction Dynamics (ULTRAFASTEUVPROBE)
Date du début: 1 nov. 2012, Date de fin: 31 oct. 2017 PROJET  TERMINÉ 

"This research is aimed at developing and validating a novel approach for time resolved imaging of structural dynamics, using single photon Coulomb explosion imaging (CEI) with ultrafast extreme UV (EUV) pulses to probe laser initiated ultrafast structural rearrangement and fragmentation dynamics. The emerging field of ultrafast EUV pulses attracts increasing amount of scientific attention, predominantly concentrated on understanding aspects of the generation process, as well as on measuring record breaking attosecond pulses at increasingly high photon energies and photon flux. I propose to direct the unique properties of ultrafast EUV pulses towards time resolved studies of molecular reaction dynamics that are inaccessible with conventional ultrafast laser systems. Time resolved single photon CEI will make possible the visualization of complex dynamics in polyatomic systems; specifically, how laser driven electronic excitation couples into nuclear motion in a wide range of molecular systems. In contrast to earlier attempts, in which CEI was driven with intense near-IR pulses that can alter the observed dynamics, the proposed single photon CEI will remove the masking intense field effects and provide a simple and general probe. A comprehensive experimental effort is proposed - to conduct a direct comparison of intense field CEI to the proposed single EUV photon approach. Successful implementation of this research will endow us with a new way to visualize and understand the underlying quantum mechanisms involved in chemical reactions. With this new technology I hope to be able to provide unique insight into molecular fragmentation and rearrangement dynamics during chemical reactions and to resolve long standing basic scientific questions, such as the concerted or sequential nature of double proton transfer in DNA base-pair models. Finally, the ""table top"" techniques developed in my lab will mature and become applicable to the emerging ultrafast EUV user facilities."