Ultrafast Nonadiabatic Dynamics of - American Chemical Society

Ultrarapide, Faculte´ des Sciences de Base, ISIC-BSP, CH-1015 Lausanne, Switzerland, and. Paul Scherrer Institut, Swiss Light Source, CH-8092 Villige...
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Published on Web 06/09/2007

Ultrafast Nonadiabatic Dynamics of [FeII(bpy)3]2+ in Solution Wojciech Gawelda,†,‡ Andrea Cannizzo,† Van-Thai Pham,† Frank van Mourik,† Christian Bressler,† and Majed Chergui*,† Contribution from the Ecole Polytechnique Fe´ de´ rale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculte´ des Sciences de Base, ISIC-BSP, CH-1015 Lausanne, Switzerland, and Paul Scherrer Institut, Swiss Light Source, CH-8092 Villigen, Switzerland Received January 26, 2007; E-mail: [email protected]

Abstract: The ultrafast relaxation of aqueous iron(II)-tris(bipyridine) upon excitation into the singlet metalto-ligand charge-transfer band (1MLCT) has been characterized by femtosecond fluorescence up-conversion and transient absorption (TA) studies. The fluorescence experiment shows a very short-lived broad 1MLCT emission band at ∼600 nm, which decays in e20 fs, and a weak emission at ∼660 nm, which we attribute to the 3MLCT, populated by intersystem crossing (ISC) from the 1MLCT state. The TA studies show a short-lived (