Charge-changing collisions of argon ions on argon gas. One-electron capture

Quenching collisions of low-energy metastable multiply charged argon ions

“…The quenching cross sections are 8.64X10 ' cm at 375 eV and 8.2X 10 ' cm at 500 eV, considerably smaller than the Ar + cross sections. These are both significantly higher than a measured single capture cross section of 2.6 X 10 ' cm at 1.2 keV but a clear energy dependence was observed for this collision [9]. At these lower energies, both the quenching and electron-transfer cross sections are likely to be energy and level dependent.…”

“…Vancura et al [7] have studied the Ar~+-Ar electron-transfer collision for 8~q~16, and this collision was earlier investigated by Klinger, Miiller, and Salzborn [8] for 2 & q &7, Aubert et al. [9] for 2~q + 12, and Barany et al [4] for 4~q & 8. Typically, only one or two electrons are gained by the projectile ions, although highly charged recoil ions are produced [10].…”

Absolute total, one-, two-, and three-electron-transfer cross sections forArq+(8≤q≤16) on Ar at 2.3qkeV

“…In the measurements described below, it is possible to have a linear variation with pressure for the one-electron-transfer cross section, and at the same time a nonlinear variation for the twoand three-electron-transfer cross sections. Furthermore, the nonlinear contribution can be comparable to the linear contribution even at very low pressures as can be calculated from expressions (1) and (2) below. The problem of multiple collision which masquerade as doubleand triple-electron capture cannot be circumvented by the use of other, e. g., coincidence, techniques.…”

“…Similarly, the probability P z(l) that an ion of charge q will undergo two and only two collisions each of which decreases its charge by one unit is I P~(l) = P', (x)Xq, , dx exp[ Xq~, (lx ) ]- (2) and so on. Carrying out the integrations in (1), and taking the arguments in the exponentials that are small compared to one, the single-collision condition, gives P' 2(l)+P 2(l) (4) These equations are the same as Eq.…”

“…Klinger, Muller, and Salzborn [1] measured one to several electron transfer cross sections for Ar~+ (2 q 7) on Ar in the 5 -15q-keV collision energy range. Aubert et al [2] measured one-electron-transfer cross sections for Ar~+ (2(q (12) on Ar in the 1 -10q-keV range; Justiniano et al [3] measured charge transfer and ionization in Art+(2&q(9) on Ne collisions in the 0.1 -1.1q-keV range.…”