Ultrafast Hybridization Screening in Fe3+ Aqueous Solution

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• 作者：Stephan Th眉rmer ; Robert Seidel ; Wolfgang Eberhardt ; Stephen E. Bradforth ; Bernd Winter
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：August 17, 2011
• 年：2011
• 卷：133
• 期：32
• 页码：12528-12535
• 全文大小：975K
• 年卷期：v.133,no.32(August 17, 2011)
• ISSN：1520-5126

文摘

We report here on the electron binding energies and ultrafast electronic relaxation of the Fe³⁺(aq) complex in FeCl₃ aqueous solution as measured by soft X-ray photoelectron (PE) spectroscopy from a vacuum liquid microjet. Covalent mixing between the 3d valence orbitals of the iron cation and the molecular orbitals of water in the ground-state solution is directly revealed by spectroscopy of the highest partially occupied molecular orbitals. Valence PE spectra, obtained for photon energies near the iron 2p absorption edge, exhibit large resonant enhancements. These resonant PE features identify 3d鈥揙2p transient hybridization between iron and water-derived orbitals and are an indication of charge transfer within the electronically excited Fe³⁺(aq)* complex. Charge transfer from water to iron is also revealed by the 2p core-level PE spectrum, and the asymmetric peak shape additionally identifies the characteristic multiplet interactions in the 2p core-hole state. The electronic structure of water molecules in the first hydration shell is selectively probed by Auger decay from water molecules, at excitation energies well below the O1s absorption edge of neat water. These experiments lay the groundwork for establishing resonant PE spectroscopy for the study of electronic-structure dynamics in the large family of transition metal (aqueous) solutions.