Sankari Anna, Stråhlman Christian, Sankari Rami, Partanen Leena, Laksman Joakim, Kettunen J Antti, Galván Ignacio Fdez, Lindh Roland, Malmqvist Per-Åke, Sorensen Stacey L
Department of Physics, Lund University, P.O. Box 118, S-22100 Lund, Sweden.
Department of Materials Science and Applied Mathematics, Malmö University, S-20506 Malmö, Sweden.
J Chem Phys. 2020 Feb 21;152(7):074302. doi: 10.1063/1.5141414.
In this paper, we examine decay and fragmentation of core-excited and core-ionized water molecules combining quantum chemical calculations and electron-energy-resolved electron-ion coincidence spectroscopy. The experimental technique allows us to connect electronic decay from core-excited states, electronic transitions between ionic states, and dissociation of the molecular ion. To this end, we calculate the minimum energy dissociation path of the core-excited molecule and the potential energy surfaces of the molecular ion. Our measurements highlight the role of ultra-fast nuclear motion in the 1a 4a core-excited molecule in the production of fragment ions. OH fragments dominate for spectator Auger decay. Complete atomization after sequential fragmentation is also evident through detection of slow H fragments. Additional measurements of the non-resonant Auger decay of the core-ionized molecule (1a ) to the lower-energy dication states show that the formation of the OH + H ion pair dominates, whereas sequential fragmentation OH + H → O + H + H is observed for transitions to higher dication states, supporting previous theoretical investigations.
在本文中，我们结合量子化学计算和电子能量分辨电子 - 离子符合光谱，研究了芯激发和芯电离水分子的衰变与碎片化过程。该实验技术使我们能够关联芯激发态的电子衰变、离子态之间的电子跃迁以及分子离子的解离。为此，我们计算了芯激发分子的最小能量解离路径以及分子离子的势能面。我们的测量突出了超快核运动在1a 4a芯激发分子产生碎片离子过程中的作用。对于旁观者俄歇衰变，OH碎片占主导。通过检测慢速H碎片，连续碎片化后的完全原子化也很明显。对芯电离分子（1a ）到低能双正离子态的非共振俄歇衰变的额外测量表明，OH + H离子对的形成占主导，而对于向更高双正离子态的跃迁，观察到连续碎片化OH + H → O + H + H，这支持了先前的理论研究。
