About the double ionization of ammonia and carbon dioxide. A comparison between photoionization and electron impact

Abstract

The double ionization of NH 3 and CO 2 is investigated by photoionization in the 30-60 eV photon energy range and electron impact from 30 to 100 eV. The lowest onset for NH 3 2+ formation, measured for the first time by photoionization, is at 34.5 ±0.2 eV. By electron impact this threshold is at 34.8 ± 0.2 eV. For CO 2 2+ this onset is measured at 37.5 ± 0.1 eV by photoionization and 38.0 ± 0.1 eV by electron impact. Close to these onsets two double-ionization energies are observed: 38.5 ± 0.1 eV by photoionization and 39.5 ± 0.2 eV by electron impact. These have probably to be ascribed to two different CO 2 2+ states. Higher-lying doubly ionized states of CO 2 are detected in the 60-100 eV electron impact energy range.

Electron ionization of CO2

“…The dissociative ionization of CO 2 has been the subject of a number of investigations employing a variety of techniques: electron-ionization mass spectrometry [4][5][6][7][8][9][10][11][12][13][14][15][16][17], photoionization mass spectrometry [18][19][20][21][22][23][24][25], collisions with positrons [26], collisions with high translational energy ions [27], ultrafast laser pulses [28] and coincidence techniques [19][20][21][23][24][25]27,29,28]. Concentrating on the previous cross determinations for electron ionization of CO 2 , the total ionization cross section has been measured from threshold to 100 eV by Asundi et al [4] and from threshold to 1000 eV by Rapp and Englander-Golden [5].…”

The dissociative ionization of carbon dioxide below 21.22eV. A high resolution PIPECO spectroscopic investigation

“…The energies range from the onset up to l00eV impinging electron energy. Using synchrotron radiation, these three fragmentation channels were investigated by mass spectrometric photoionization between 35 and 60eV photon energy [8]. There are very few studies which include the translational energy measurements of the fragment ions [1].…”

The dissociative electroionization of carbon dioxide by low-energy electron impact. The C+, O+ and CO+ dissociation channels

“…The double ionization of CO 2 and its dissociation, investigated by electron impact and mass spectrometric photoionization, have already been reported [23].…”