Single ionization of calcium by electron impact

Abstract

Relative cross sections for the single ionization of calcium were measured in the energy range from threshold to 100.7 eV using a time-of-flight ion detection method. Simultaneous detection of the ions from ionization of water molecules was used to monitor and eliminate energy-dependent effects. Present cross sections are normalized at 40 eV using previous experimental data. A comparison is made with existing partial cross sections for Ca + as well as total ionization cross sections to highlight the significant difference which exists in the energy shape and magnitude of the cross section maximum.

Measurement of electron-calcium ionization integral cross section using an ion trap with a low-energy, pulsed electron gun

“…The obtained ICS results are in general in good qualitative agreement with existing data sets [12,26,28]. The energy of ICS maximum reproduces data of Cvejanović and Murray [12] and is quite close (slightly higher energy) to the maxima of Okudaira et al [26] and Fiquet-Fayard and Lahmani [28].…”

“…As only relative values of cross sections were measured, the results were normalized to the experimental 100.5 eV point of Cvejanović and Murray [12] (the lowest uncertainty data points among energy-overlapping ranges of both experiments). The results are presented in figure 10.…”

“…The energies of such electrons are high above the ionization thresholds and typical electron impact ionization cross sections maxima of atoms and molecules. For example the maximum of cross section for calcium is noticed at around 25 eV [12], typical molecules like CO 2 have their ionization maxima at about 100 eV [13,14]. This way, the cross sections have usually low value at energies above 1 keV, making the electron impact inefficient for ion derivation.…”

Coplanar symmetric (e, 2e) measurements from calcium at low energy

“…Early studies measured total ionization cross-sections by detecting the ions as a function of the incident electron energy [30][31][32][33][34]. Recent experiments by Cvejanovic and Murray [35] also measured the ion yield as a function of impact energy, and placed the results on an absolute scale by normalizing to the ionization cross-section for H 2 O which is well known. These new results showed similarities to the early cross-section measurements, but clear differences were seen in both the magnitude and structure.…”

The Method of Interacting Configurations in Complex Number Representations: From Helium to the Complex Atoms

“…As one can see in the literature, beryllium , magnesium [15,16,18,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] and calcium [52][53][54][55][56][57][58] 2 Few other well-defined and popular methods of atomic characteristics calculations…”