Triple coincidence experiments to study the fragmentation of core ionized molecules by electron impact

Stability and dissociation dynamics of N2++ ions following core ionization studied by an Auger-electron–photoion coincidence method

“…15 To our knowledge, there has been no theoretical work on potential energy curves for more highly excited dicationic states than the outer valence two hole states. Since no vibrational structure for such highly excited states has been observed in the previous experimental work, 3,5 we deduce that there is no local minimum in the potential energy curve for the 1 31 This observation was attributed to Auger decay following the 1s shake-off states, which is completely eliminated in the present study by tuning the photon energy to the near-threshold region, as mentioned in Sec. II.…”

Dissociative double photoionization of N2 using synchrotron radiation: Appearance energy of the N2+ dication

“…8,12,40 In the total ion yield spectrum of Fig. 2 we see no evidence of such channel, but this is not surprising since, according to the Wannier inter- FIG.…”

“…4, all such values are several eV higher than the thermodynamic limit for dissociation into a͒ N 2+ ͑ 2 P͒ +N͑ 4 S͒ at 53.92 eV, 12 but they are lower than the triple ionization channel leading to N 2+ ͑ 2 P͒ +N + ͑ 3 P͒ at 68.47 eV via Coulomb explosion. 12 In the case of photon excitation, cross sections for CAD photoionization of N 2 in synchrotron radiation experiments have been measured only in the high energy range from 100 to 800 eV, 9 and the threshold for production of N 2+ has not been investigated. The cross section for the CAD channel ͑equal to 0.018 Mb, with 1 Mb= 10 −18 cm 2 , at 100 eV͒ is much smaller than either that for the Coulomb explosion ͑0.916 Mb, at 100 eV͒, or the non dissociative ionization channel ͑1.14 Mb, at 100 eV͒.…”

“…following either electron impact dissociative ionization, [1][2][3][4][5][6][7][8] single photon ionization, 9 inner shell ionization with soft X-ray radiation, [10][11][12] or multiphoton processes induced by high intensity lasers in both UV ͑Refs. 13-15͒ and near-IR ͑Refs.…”

Analysis of electron impact ionization properties of methane

“… Tawara et al [1973] measured the X‐ray emission cross section due to K‐shell (1a 1 ) excitation of CH 4 in the 0.3–18 keV range and found that the emission yield is independent of incident electron energy. Fainelli et al [2002] investigated the fragmentation of core ionized CH 4 by electron impact. Malhi et al [1987], Knudsen et al [1995], and Luna et al [2003] reported partial ionization cross sections by proton impact.…”