Electron impact ionization of argon ions (q  4 11)

Abstract

Absolute cross sections for electron impact ionization of multiply charged argon ions (Arq+) have been measured in an animated crossed electron–ion beam experiment. Results are reported for single ionization (SI) (q = 4–6, 8, 10 and 11) ions and for double ionization (DI) (q = 5–11). The measurements cover the energy range from threshold to about 6000 eV. The direct process is seen to dominate SI for q = 8, 10 and 11. For charge states 4–6, excitation–autoionization processes are seen to largely contribute to the ionization signal. In addition, metastable states are unambiguously identified for Ar5+ and Ar6 +. Ionization–autoionization (IA) from the L shell accounts predominantly for DI of Arq+ (q = 5, 6). For charge states 7–11 direct DI is found to decrease strongly with respect to IA from the K shell.

X-ray emission from thin plasmas

“…In the case of Ar vii, the measurements of Chung (1996) do not show evidence of 3s3p 3 P metastable ions unlike Djuric et al (1993b), Howald et al (1986) and Zhang et al (2002). However, they only extend up to u = 6, where they seem to be in good agreement with Zhang et al (2002), which contains data till 30 times the threshold.…”

“…We decided not to include the measurements for Ar viii (Rachafi et al 1991;Zhang et al 2002) and Cr xiv (Gregory et al 1990), because they are higher and lower, respectively, compared with the other elements on this sequence. The Ar viii measurements are probably affected by the presence of resonant excitation double Auger ionization (REDA).…”

Laser-Cluster Interaction: X-Ray Production by Short Laser Pulses

“…, where the empirical parameters A * q and W * q were obtained by a fit to experimental ion-atom collision data [4,22]. The cluster-specific effects of suppression of the work function can be incorporated by modifying the effective work function W * q in the presence of nearby ionic cores.…”

Absolute rate coefficients for photorecombination and electron-impact ionization of magnesiumlike iron ions from measurements at a heavy-ion storage ring

“…II A). Ionization signal below the ground-level ionization threshold has been observed in all of the single-pass EII measurements for Mg-like ions [17][18][19][20][21][22][23].…”

“…For the EII measurements discussed in Sec. I B, no REDA or READI resonances were observed for most other ions from the Mg-like isoelectronic sequence [17][18][19][20][21][22] due to limited energy resolution, limited statistical accuracy, and the use of coarse experimental energy grids in these measurements. An exception is the recent study of Becker et al [23] who measured the cross section for EII of Ar 6+ on a fine energy grid with sufficiently low statistical uncertainties for the observation of REDA and READI resonances.…”