Premium
Negative‐ion/positive‐ion coincidence spectroscopy as a tool to identify anionic fragments: The case of core‐excited CHF 3
Author(s) -
Kivimäki Antti,
Stråhlman Christian,
Sankari Rami,
Richter Robert
Publication year - 2020
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.4487
Subject(s) - chemistry , ion , dissociation (chemistry) , excited state , coincidence , spectroscopy , ionization , atomic physics , analytical chemistry (journal) , physics , medicine , alternative medicine , organic chemistry , pathology , quantum mechanics , chromatography
We have studied the dissociation of the trifluoromethane molecule, CHF 3 , 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 F 2 − . 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.