Ahsan Md Sabbir, Kochetov Vladislav, Hein Dennis, Bokarev Sergey I, Wilkinson Iain
Department of Locally-Sensitive and Time-Resolved Spectroscopy, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
Phys Chem Chem Phys. 2022 Jun 29;24(25):15540-15555. doi: 10.1039/d1cp05840a.
Liquid-microjet-based X-ray photoelectron spectroscopy was applied to aqueous triiodide solutions, I, to investigate the anion's valence- and core-level electronic structure, ionization dynamics, associated electron-correlation effects, and nuclear geometric structure. The roles of multi-active-electron (shake-up) ionization processes - with noted sensitivity to the solute geometric structure - were investigated through I solution valence, I 4d, and I 3d core-level measurements. The experimental spectra were interpreted with the aid of simulated photoelectron spectra, built upon multi-reference electronic structure calculations associated with different I molecular geometries. A comparison of the single-to-multi-active-electron ionization signal ratios extracted from the experimental and theoretical core-level photoemission spectra suggests that the ground state of the solute adopts a near-linear average geometry in aqueous solutions. This contrasts with the interpretation of time-resolved X-ray solution scattering studies, but is found to be fully consistent with the rest of the solution-phase I literature. Comparing the results of low- and high-photon-energy photoemission measurements, we further suggest that the aqueous anion adopts a more asymmetric geometry at the aqueous-solution-gas interface than in the aqueous bulk.
基于液体微喷射的X射线光电子能谱被应用于三碘化物水溶液（I），以研究该阴离子的价层和内层电子结构、电离动力学、相关的电子关联效应以及核几何结构。通过对I溶液的价层、I 4d和I 3d内层测量，研究了对溶质几何结构具有显著敏感性的多活性电子（振激）电离过程的作用。借助基于与不同I分子几何结构相关的多参考电子结构计算构建的模拟光电子能谱，对实验光谱进行了解释。从实验和理论内层光发射光谱中提取的单活性电子与多活性电子电离信号比的比较表明，溶质的基态在水溶液中采用近线性平均几何结构。这与时间分辨X射线溶液散射研究的解释形成对比，但被发现与其余的溶液相I文献完全一致。比较低光子能量和高光子能量光发射测量的结果，我们进一步表明，与水相主体相比，水相阴离子在水溶液 - 气体界面采用更不对称的几何结构。
