Probing Transient Valence Orbital Changes with Picosecond Valence-to-Core X-ray Emission Spectroscopy

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• 作者：Anne Marie MarchTadesse A. Assefa ; Christina Boemer ; Christian Bressler ; Alexander Britz ; Michael Diez ; Gilles Doumy ; Andreas Galler ; Manuel Harder ; Dmitry Khakhulin ; Zoltán Németh ; Mátyás Pápai ; Sebastian Schulz ; Stephen H. Southworth ; Hasan Yavaş ; Linda Young ; Wojciech Gawelda ; György Vankó
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 9, 2017
• 年：2017
• 卷：121
• 期：5
• 页码：2620-2626
• 全文大小：475K
• ISSN：1932-7455

文摘

We probe the dynamics of valence electrons in photoexcited [Fe(terpy)₂]²⁺ in solution to gain deeper insight into the Fe–ligand bond changes. We use hard X-ray emission spectroscopy (XES), which combines element specificity and high penetration with sensitivity to orbital structure, making it a powerful technique for molecular studies in a wide variety of environments. A picosecond-time-resolved measurement of the complete 1s X-ray emission spectrum captures the transient photoinduced changes and includes the weak valence-to-core (vtc) emission lines that correspond to transitions from occupied valence orbitals to the nascent core-hole. Vtc-XES offers particular insight into the molecular orbitals directly involved in the light-driven dynamics; a change in the metal–ligand orbital overlap results in an intensity reduction and a blue energy shift in agreement with our theoretical calculations and more subtle features at the highest energies reflect changes in the frontier orbital populations.