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
Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq), Institute of Methods for Material Development, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489, Berlin, Germany.
Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059, Rostock, Germany.
Chemphyschem. 2017 Mar 3;18(5):465-469. doi: 10.1002/cphc.201601396. Epub 2017 Jan 19.
Photoinduced spin-flip in Fe 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) ] , 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.
铁配合物中的光致自旋翻转是一种超快现象，有潜力成为传统信息处理和磁存储的替代方法。在可见光最初激发进入单重态金属到配体电荷转移态之后，向高自旋五重态的电子跃迁可能会经历不同的路径。在这里，我们应用超快XUV（极紫外）光电子能谱，通过以飞秒时间分辨率监测激发态之间的瞬态电子密度分布，来追踪水溶液中铁三联吡啶配合物[Fe(bpy)₃]²⁺ 中从低自旋到高自旋的动力学过程。借助第一性原理计算，这种方法使我们能够明确揭示从单重态到五重态的顺序和直接去激发路径，分支比为4.5:1。
