We have studied the dissociation of the trifluoromethane molecule, CHF3 , into negative ionic fragments at the C 1s and F 1s edges. The measurements were performed by detecting coincidences between negative and positive ions. We observed five different negative ions: F- , H- , C- , CF- , and F2 - . Their production was confirmed by the analysis of triple coincidence events (negative-ion/positive-ion/positive-ion or NIPIPI coincidences) that were recorded with cleaner signals than those of the negative-ion/positive-ion coincidences. The intensities of the most intense NIPIPI coincidence channels were recorded as a function of photon energy across the C 1s and F 1s excitations and ionization thresholds. We also observed dissociation channels involving the formation of one negative ion and three positive ions. Our results demonstrate that negative-ion/positive-ion coincidence spectroscopy is a very sensitive method to observe anions, which at inner-shell edges are up to three orders of magnitude less probable dissociation products than cations.

中文翻译：

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负离子/正离子符合光谱法可作为识别阴离子碎片的工具：核激发的CHF3。

我们已经研究了三氟甲烷分子CHF3在C 1s和F 1s边缘解离为负离子片段。通过检测负离子与正离子之间的重合来进行测量。我们观察到五个不同的负离子：F-，H-，C-，CF-和F2-。通过分析三次重合事件（负离子/正离子/正离子或NIPIPI重合），证实了它们的产生，这些事件比负离子/正离子重合的信号更清晰。在C 1s和F 1s激发和电离阈值上，最强的NIPIPI重合通道的强度被记录为光子能量的函数。我们还观察到解离通道涉及一个负离子和三个正离子的形成。