Single ionisation of multiply charged xenon ions by electron impact

Achenbach, C.; Müller, A.; Salzborn, E.; Becker, R.

doi:10.1088/0022-3700/17/7/023

Cited by 57 publications

(31 citation statements)

References 33 publications

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“…With this method it is not necessary to make a separate measurement of the form factor which describes the overlap of both beams and, furthermore, each ionization cross section determined is independently absolute. A remeasurement of the cross section o- 12 for Ar 1+ ions yielded very good absolute agreement with data published by Woodruff, Hublet, and Harrison 8 on which we had to rely in previous experiments 9 for absolute calibration. Apart from the new experimental procedure the setup used here was basically the same as that employed before.…”

Section: R Beckersupporting

confidence: 79%

Collision-Strength Shift in Electron-Impact Single and Double Ionization of Sb and Bi Ions

et al. 1985

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At energies greater than 200 eV the electron-impact single-ionization cross sections for Sb 2 + (4d l0 5s 2 5p) and Bi 2+ (5d l0 6s 2 6p) ions, o-2 ,3, are larger than the corresponding cross sections, 0x2, for Sb 1 + and Bi 1 + ions, respectively. This extraordinary behavior is a consequence of the fact that the 4d(5d) hole configurations goes from autoionization to bound when the charge state of the Sb (Bi) ions is increased from +1 to + 2. Additionally, multiple ionization measurements (0-1,3 for Sb and ox3, 0-2,4, and 0-3,5 for Bi) are presented for electron energies up to about 1000 eV.PACS numbers: 34.80.DpRecently, some basic understanding has been gained on multiple ionization of atomic ions via single collisions with electrons. 1 " 4 The large cross sections observed, especially for complex ions, may be attributed to single-ionization events ejecting an electron from one of the inner shells followed by the emission of one or more additional electrons via autoionization processes. However, no adequate attention has yet been given to the mutual interdependence of multiple and single electron-impact ionization of ions: Collision strength from a given subshell missing in the cross section v qfq + \ for single ionization of a #-fold charged ion can be found in the cross section o-qg + 2 for double ionization and vice versa depending on the possibility of an inner-shell ionization-autoionization mechaism.In this Letter we discuss the shift of d electron collision strength between single and double ionization of Sb« + (tf-1,2) and Bi« + (# =1,2,3) ions which are homologous with configurations 4d l0 5s 2 5p 3~q and 5d l0 6s 2 6p 3~Q , respectively. The starting point of this investigation was the observation of an unusual behavior of cross sections ox,2 an d °*2,3 f°r Sb 1 + (Bi 1+ ) and Sb 2+ (Bi 2+ ) ions, respectively. At electron energies above about 200 eV we found o-2 ,3 > (7i )2 ; i.e., for these species it is easier to remove an electron from the doubly charged ion (ionization potentials 5 of 25.3 eV for Sb 2 + and 26.6 eV for Bi 2 + ) than to remove an electron from the singly charged ion (ionization potentials 5 of 16.24 eV for Sb 1+ and 16.69 eV for Bi 1 + ). A second important experimental result is the observation of the largest cross sections for double ionization ever found for an atomic ion with ox3~6.5xl0" 17 cm 2 for Sb 1+ and ox, 3~7 .5 xl0" 17 'cm 2 for Bi 1+ , while the ions Bi 2+ and Bi 3 + have considerably smaller double-ionization cross sections (0-2,4-2.7 xlO" 17 cm 2 and 0-3,5-1.9 xlO" 17 cm 2 at maximum) and are almost equal above 500 eV. We will demonstrate below that this extraordinary behavior is due to the fact that the 4d (5d) hole configuration goes from autoionizing to bound as one goes fromSb 1+ (Bi 1+ ) toSb 2+ (Bi 2 + ) ions.For the measurement of ionization cross sections we have employed a new experimental technique 6 with crossed electron and ion beams which is based on the "animated-beams method 7 " of Brouillard and coworkers. However, instead of sweeping the electron b...

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Section: R Beckersupporting

confidence: 79%

Collision-Strength Shift in Electron-Impact Single and Double Ionization of Sb and Bi Ions

et al. 1985

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“…For He ii, the cross-sections of Peart et al (1969) have been selected instead of Dolder et al (1961), Defrance et al (1987) and Achenbach et al (1984), because they have a larger extension to the highest energies and an acceptable uncertainty of 12%, compared to Dolder et al (1961) with 25%.…”

Section: H Isoelectronic Sequencementioning

confidence: 99%

“…7. The DI normalized cross-section for Ne ii (dashed blue line) and the measurements of Achenbach et al (1984) (red dots), Diserens et al (1984) (green triangle), Donets & Ovsyannikov (1981) (blue square) and Man et al (1987a) (cyan square) with their respective experimental uncertainties.…”

Section: Di: 2p Cross Sectionmentioning

confidence: 99%

X-ray emission from thin plasmas

Urdampilleta

Kaastra

Mehdipour

2017

A&A

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Every observation of astrophysical objects involving a spectrum requires atomic data for the interpretation of line fluxes, line ratios, and ionization state of the emitting plasma. One of the processes that determines it is collisional ionization. In this study, an update of the direct ionization (DI) and excitation-autoionization (EA) processes is discussed for the H to Zn-like isoelectronic sequences. In recent years, new laboratory measurements and theoretical calculations of ionization cross-sections have become available. We provide an extension and update of previous published reviews in the literature. We include the most recent experimental measurements and fit the cross-sections of all individual shells of all ions from H to Zn. These data are described using an extension of Younger's and Mewe's formula, suitable for integration over a Maxwellian velocity distribution to derive the subshell ionization rate coefficients. These ionization rate coefficients are incorporated in the high-resolution plasma code and spectral fitting tool SPEX V3.0.

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“…16 According to the experimental data, 17 doubly-ionized ions was observed in the microwave neutralizer, thus stepwise ionization from singly-ionized ions to doubly-ionized ions was also implemented in the present model. 18 Recombination processes were ignored due to its fairly low probability.…”

Section: B Hybrid-pic Modelmentioning

confidence: 99%

Numerical Simulation of Microwave Neutralizer Including Ion’s Kinetic Effects

Kubota

Watanabe

Yamamoto

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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In order to analyze a microwave neutralizer in ion's time/space scales, a threedimensional Hybrid-PIC (Particle-In-Cell) solver which treats ions and electrons as particles and fluid was developed. In this analysis, microwave power absorption distribution was estimated by means of another electromagnetic PIC solver. The results show that qualitative agreement on voltage-current characteristics was achieved, whereas a discontinuous current jump between a low current mode and a high current mode was still diffused. It is found that, in the high current mode, the electric potential is gradually increased toward the plume region inside the orifice, which promotes high ion production rate there. It is also shown that the sputtering rate of an antenna is comparable with the measured data, where doublyionized ions mainly produced inside the orifice considerably aggravate the sputtering rate. NomenclatureB = magnetic flux density C = thermal velocity E = electric field e = elementary charge H = magnetic field j = current density k = Boltzmann constant m = mass of particle n = number density P = input power p = pressure 2 q = heat flux T = temperature t = time u = velocity of fluid v = velocity of a particle x = coordinate β = Hall parameter φ = electric potential μ = mobility ν = collision frequency ω p = plasma frequency subscripts abs : absorption anm : anomalous e : electron h : heavy particle (neutral and ion) i : ion s : space (basically represents x = 26 mm) sh : sheath

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Single ionisation of multiply charged xenon ions by electron impact

Cited by 57 publications

References 33 publications

Collision-Strength Shift in Electron-Impact Single and Double Ionization of Sb and Bi Ions

Collision-Strength Shift in Electron-Impact Single and Double Ionization of Sb and Bi Ions

X-ray emission from thin plasmas

Numerical Simulation of Microwave Neutralizer Including Ion’s Kinetic Effects

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