Koulentianos D, Carniato S, Püttner R, Martins J B, Travnikova O, Marchenko T, Journel L, Guillemin R, Ismail I, Céolin D, Piancastelli M N, Feifel R, Simon M
Sorbonne Université, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris Cedex 05, France.
Phys Chem Chem Phys. 2021 May 14;23(18):10780-10790. doi: 10.1039/d1cp00607j. Epub 2021 Apr 28.
Using synchrotron radiation in the tender X-ray regime, a photoelectron spectrum showing the formation of single site double-core-hole pre-edge states, involving the K shell of the O atom in CO, has been recorded by means of high-resolution electron spectroscopy. The experimentally observed structures have been simulated, interpreted and assigned, employing state-of-the-art ab initio quantum chemical calculations, on the basis of a theoretical model, accounting for their so-called direct or conjugate character. Features appearing above the double ionization threshold have been reproduced by taking into account the strong mixing between multi-excited and continuum states. The shift of the σ* resonance below the double ionization threshold, in combination with the non-negligible contributions of multi-excited configurations in the final states reached, gives rise to a series of avoided crossings between the different potential energy curves.
利用软X射线波段的同步辐射，通过高分辨率电子能谱记录了一个光电子能谱，该能谱显示了单中心双核空穴前边缘态的形成，涉及CO中O原子的K壳层。基于一个理论模型，利用最先进的从头算量子化学计算，对实验观测到的结构进行了模拟、解释和归属，该模型考虑了它们所谓的直接或共轭特征。通过考虑多激发态和连续态之间的强混合，再现了双电离阈值以上出现的特征。双电离阈值以下σ*共振的移动，再加上所达到的末态中多激发组态不可忽略的贡献，导致了不同势能曲线之间的一系列避免交叉。
