Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France.
Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France.
Phys Chem Chem Phys. 2023 Jan 4;25(2):1063-1074. doi: 10.1039/d2cp03488c.
Fragmentation dynamics of core-excited isolated ammonia molecules is studied by two different and complementary experimental methods, high-resolution resonant Auger spectroscopy and electron energy-selected Auger electron-photoion coincidence spectroscopy (AEPICO). The combined use of these two techniques allows obtaining information on different dissociation patterns, in particular fragmentation before relaxation, often called ultrafast dissociation (UFD), and fragmentation after relaxation. The resonant Auger spectra contain the spectral signature of both molecular and fragment final states, and therefore can provide information on all events occurring during the core-hole lifetime, in particular fragmentation before relaxation. Coincidence measurements allow correlating Auger electrons with ionic fragments from the same molecule, and relating the ionic fragments to specific Auger final electronic states, and yield additional information on which final states are dissociative, and which ionic fragments can be produced in timescales either corresponding to the core-hole lifetime or longer. Furthermore, we show that by the combined use of two complementary experimental techniques we are able to identify more electronic states of the NH fragment with respect to the single one already reported in the literature.
通过两种不同且互补的实验方法，即高分辨率共振俄歇谱和电子能量选择俄歇电子-光电子符合能谱（AEPICO），研究了核心激发孤立氨分子的碎裂动力学。这两种技术的结合使用可以获得关于不同解离模式的信息，特别是弛豫前的碎裂，通常称为超快解离（UFD），以及弛豫后的碎裂。共振俄歇谱包含分子和碎片终态的光谱特征，因此可以提供核心空位寿命期间发生的所有事件的信息，特别是弛豫前的碎裂。符合测量允许将俄歇电子与同一分子的离子碎片相关联，并将离子碎片与特定的俄歇终电子态相关联，从而提供有关哪些终态是离解的，以及在与核心空位寿命或更长时间对应的时间尺度上可以产生哪些离子碎片的附加信息。此外，我们表明，通过两种互补实验技术的结合使用，我们能够识别出 NH 碎片的更多电子态，而不是文献中已经报道的单一电子态。
