Haags Anja, Yang Xiaosheng, Egger Larissa, Brandstetter Dominik, Kirschner Hans, Bocquet François C, Koller Georg, Gottwald Alexander, Richter Mathias, Gottfried J Michael, Ramsey Michael G, Puschnig Peter, Soubatch Serguei, Tautz F Stefan
Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Jülich, Germany.
Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, Jülich, Germany.
Sci Adv. 2022 Jul 22;8(29):eabn0819. doi: 10.1126/sciadv.abn0819.
Tracing the modifications of molecules in surface chemical reactions benefits from the possibility to image their orbitals. While delocalized frontier orbitals with π character are imaged routinely with photoemission orbital tomography, they are not always sensitive to local chemical modifications, particularly the making and breaking of bonds at the molecular periphery. For such bonds, σ orbitals would be far more revealing. Here, we show that these orbitals can indeed be imaged in a remarkably broad energy range and that the plane wave approximation, an important ingredient of photoemission orbital tomography, is also well fulfilled for these orbitals. This makes photoemission orbital tomography a unique tool for the detailed analysis of surface chemical reactions. We demonstrate this by identifying the reaction product of a dehalogenation and cyclodehydrogenation reaction.
追踪表面化学反应中分子的修饰得益于对其轨道进行成像的可能性。虽然具有π特征的离域前沿轨道通常通过光发射轨道断层扫描成像，但它们并不总是对局部化学修饰敏感，特别是分子外围化学键的形成和断裂。对于此类化学键，σ轨道的揭示能力要强得多。在此，我们表明这些轨道确实可以在非常宽的能量范围内成像，并且平面波近似（光发射轨道断层扫描的一个重要组成部分）对于这些轨道也能很好地满足。这使得光发射轨道断层扫描成为详细分析表面化学反应的独特工具。我们通过鉴定脱卤和环脱氢反应的反应产物来证明这一点。
