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Ultrafast Spin Crossover in [Fe II (bpy) 3 ] 2+ : Revealing Two Competing Mechanisms by Extreme Ultraviolet Photoemission Spectroscopy
Author(s) -
Moguilevski Alexandre,
Wilke Martin,
Grell Gilbert,
Bokarev Sergey I.,
Aziz Saadullah G.,
Engel Nicholas,
Raheem Azhr A.,
Kühn Oliver,
Kiyan Igor Yu.,
Aziz Emad F.
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201601396
Subject(s) - excited state , chemistry , extreme ultraviolet , spectroscopy , ultrafast laser spectroscopy , femtosecond , spin states , excitation , singlet state , atomic physics , ultrashort pulse , chemical physics , electron spectroscopy , spin crossover , density functional theory , femtochemistry , molecular physics , crystallography , physics , computational chemistry , laser , quantum mechanics , optics
Photoinduced spin‐flip in Fe II complexes is an ultrafast phenomenon that has the potential to become an alternative to conventional processing and magnetic storage of information. Following the initial excitation by visible light into the singlet metal‐to‐ligand charge‐transfer state, the electronic transition to the high‐spin quintet state may undergo different pathways. Here we apply ultrafast XUV (extreme ultraviolet) photoemission spectroscopy to track the low‐to‐high spin dynamics in the aqueous iron tris‐bipyridine complex, [Fe(bpy) 3 ] 2+ , by monitoring the transient electron density distribution among excited states with femtosecond time resolution. Aided by first‐principles calculations, this approach enables us to reveal unambiguously both the sequential and direct de‐excitation pathways from singlet to quintet state, with a branching ratio of 4.5:1.