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Ultrafast electron transfer processes studied by pump‐repump‐probe spectroscopy
Author(s) -
Fischer Martin K.,
Gliserin Alexander,
Laubereau Alfred,
Iglev Hristo
Publication year - 2011
Publication title -
journal of biophotonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 66
eISSN - 1864-0648
pISSN - 1864-063X
DOI - 10.1002/jbio.201000099
Subject(s) - ultrashort pulse , spectroscopy , femtochemistry , femtosecond , electron transfer , ultrafast laser spectroscopy , chemistry , excitation , electron , quenching (fluorescence) , aqueous solution , time resolved spectroscopy , pulse (music) , fluorescence spectroscopy , electron spectroscopy , analytical chemistry (journal) , photochemistry , radical , atomic physics , fluorescence , laser , optics , physics , chromatography , quantum mechanics , organic chemistry , detector
The photodetachment of Br – , I – and OH – in aqueous solution is studied by 2‐ and 3‐pulse femtosecond spectroscopy. The UV excitation leads to fast electron separation followed by formation of a donor‐electron pairs. An additional repump pulse is used for secondary excitation of the intermediates. The 3‐pulse technique allows distinguishing the pair‐intermediate from the fully separated electron. Using this method we observe a novel geminate recombination channel of.OH with adjacent hydrated electrons. The process leads to an ultrafast quenching (0.7 ps) of almost half the initial number of radicals. The phenomenon is not observed in Br – and I – . Our results demonstrate the potential of the 3‐pulse spectroscopy to elucidate the mechanism of ultrafast ET reactions. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)