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Gregory, D. C.; Lj, Wang; Meyer, F.W.; Rinn, K

doi:10.1103/physreva.35.3256

Cited by 96 publications

(66 citation statements)

References 30 publications

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“…The dotted curves in the figure indicate the 1σ systematic uncertainty due to the ion current calibration. The figure also shows the experimental results of Gregory et al (1987), the fit to that data used in the CIE calculations of Arnaud & Raymond (1992), and the Flexible Atomic Code (FAC) DW calculation of Dere (2007). Figure 1 shows that the crossed beams measurement of Gregory et al (1987) is about 30% larger than the current measurement.…”

Section: Results For Single Ionizationmentioning

confidence: 99%

“…The EISI cross section measured by that experiment was about 30% larger than that predicted by the distorted wave (DW) calculations of Pindzola et al (1986) or Dere (2007). Gregory et al (1987) compared their experimental result to theoretical calculations for ionization from the ground and metastable levels and concluded that the discrepancy was due to a large metastable population in the ion beam in the experiment. The measurements reported here, by being able to generate nearly pure ground state ion beams, can resolve this issue and also provide an excellent test case to compare crossed beams experimental results with the storage ring technique.…”

Section: Introductionmentioning

confidence: 99%

“…EISI of Fe 11+ has already been the subject of some theoretical and experimental work (Younger 1983;Pindzola et al 1986; Gregory et al 1987;Dere 2007). Gregory et al (1987) measured the ionization cross section for Fe 11+ using a single-pass experimental geometry.…”

Section: Introductionmentioning

confidence: 99%

“…Gregory et al (1987) measured the ionization cross section for Fe 11+ using a single-pass experimental geometry. The EISI cross section measured by that experiment was about 30% larger than that predicted by the distorted wave (DW) calculations of Pindzola et al (1986) or Dere (2007).…”

Section: Introductionmentioning

confidence: 99%

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STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe¹¹⁺FORMING Fe¹²⁺AND Fe¹³⁺

Hahn¹,

Bernhardt²,

Grieser³

et al. 2011

ApJ

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We report ionization cross section measurements for electron impact single ionization (EISI) of Fe 11+ forming Fe 12+ and electron impact double ionization (EIDI) of Fe 11+ forming Fe 13+ . The measurements cover the center-of-mass energy range from approximately 230 eV to 2300 eV. The experiment was performed using the heavy-ion storage ring TSR located at the Max-Planck-Institut für Kernphysik in Heidelberg, Germany. The storage ring approach allows nearly all metastable levels to relax to the ground state before data collection begins. We find that the cross section for single ionization is 30% smaller than was previously measured in a single-pass experiment using an ion beam with an unknown metastable fraction. We also find some significant differences between our experimental cross section for single ionization and recent distorted wave (DW) calculations. The DW Maxwellian EISI rate coefficient for Fe 11+ forming Fe 12+ may be underestimated by as much as 25% at temperatures for which Fe 11+ is abundant in collisional ionization equilibrium. This is likely due to the absence of 3s excitation-autoionization (EA) in the calculations. However, a precise measurement of the cross section due to this EA channel was not possible because this process is not distinguishable experimentally from electron impact excitation of an n = 3 electron to levels of n 44 followed by field ionization in the charge state analyzer after the interaction region. Our experimental results also indicate that the EIDI cross section is dominated by the indirect process in which direct single ionization of an inner shell 2l electron is followed by autoionization, resulting in a net double ionization.

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Section: Results For Single Ionizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe¹¹⁺FORMING Fe¹²⁺AND Fe¹³⁺

Hahn¹,

Bernhardt²,

Grieser³

et al. 2011

ApJ

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“…At low or moderate densities, ion dynamics play an important role near the center as confirmed by new experimental results (2,3,4) for Lyman and Balmer lines. Computer simulations were employed successfully for investigations of these effects (5)(6)(7)(8). In these computations, electron broadening is accounted for using an impact operator; the ionic contribution is obtained by numerical integration of the atomic Schrodinger equation for a set of ionic mocrofield formed by superposition of Debye-screened fields from uncorrelated particles.…”

Section: Hydrogen or Hydrogenic Linesmentioning

confidence: 99%

Working Group 3: Collision Processes

Dalgarno¹

1988

Trans. Int. Astron. Union

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Electron impact ionization in K‐, L‐, and M‐shells of atomic targets

Patoary

Uddin

Haque

et al. 2011

Int J of Quantum Chemistry

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ABSTRACT:Recently proposed extension of the empirical model (BELL) of Bell et al. (J Phys Chem Ref Data 1983, 12, 891) with incorporation of the quantum mechanical form of orbital radius from the DM model and a nonlinear feature in addition to the ionic and relativistic corrections is examined for electron-impact single ionization in the K-, L-, and M-shells of ionic and neutral atoms. This leads to the generalization of the parameters of the nonlinear form of the modified BELL (NMBELL) model in terms of the quantum numbers nl of the ionizing orbits. The generalization shows that only three species-independent fitting parameters, dependent only on the orbitals, in the NMBELL model satisfactorily reproduce the electron-impact single ionization cross sections of 42 ionic targets belonging to the He, Li, Be, B, C, O, F, Ne, Mg, Al, P, Ca, and Sc isoelectronic sequences over a wide range of energies up to 200 MeV. The NMBELL model is also found to well account for the L-and M-shell ionization of six neutral atoms up to 1 GeV.

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Electron-impact ionization of iron ions:Fe11+,Fe13

Cited by 96 publications

References 30 publications

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe¹¹⁺FORMING Fe¹²⁺AND Fe¹³⁺

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe¹¹⁺FORMING Fe¹²⁺AND Fe¹³⁺

Working Group 3: Collision Processes

Electron impact ionization in K‐, L‐, and M‐shells of atomic targets

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Electron-impact ionization of iron ions:Fe11+,Fe13

Cited by 96 publications

References 30 publications

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe11+FORMING Fe12+AND Fe13+

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe11+FORMING Fe12+AND Fe13+

Working Group 3: Collision Processes

Electron impact ionization in K‐, L‐, and M‐shells of atomic targets

Contact Info

Product

Resources

About

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe¹¹⁺FORMING Fe¹²⁺AND Fe¹³⁺

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe¹¹⁺FORMING Fe¹²⁺AND Fe¹³⁺