Negative‐ion/positive‐ion coincidence spectroscopy as a tool to identify anionic fragments: The case of core‐excited CHF3 |
| |
Authors: | Antti Kivim ki,Christian Str hlman,Rami Sankari,Robert Richter |
| |
Affiliation: | Antti Kivimäki,Christian Stråhlman,Rami Sankari,Robert Richter |
| |
Abstract: | 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. |
| |
Keywords: | C 1s CHF3 core ionization and excitation F 1s ion‐ion coincidence techniques negative ions photodissociation |
|
|