Experimental study of the deep-lying dielectronic recombination resonances of He-like germanium ions

Abstract

Dielectronic recombination (DR) for He-like Ge 30+ through both one-electronone-photon and two-electron-one-photon (TEOP) stabilization of Li-like doubly excited states was studied with the Heidelberg electron beam ion trap. The DR resonance strength from He-like Ge 30+ 1s 2 1 S 0 to the Li-like Ge 29+ specific configuration 1s2s 2 2 S 1/2 was determined to be (2.02 ± 0.2) × 10 −20 cm 2 eV and the total KLL DR resonance strength was determined to be (63.7 ± 6.5) × 10 −20 cm 2 eV. The experimental results agree well with a theoretical prediction obtained with the configuration interaction Hartree-Fock method.

Theoretical study of the KLL dielectronic recombination for highly charged iodine ions

“…2, the result of the present calculation for iodine ion is plotted along with these previous measurements and calculations. The solid circles are experimental values [2,3,7,20,21], while the open circles are theoretical values [11,22,23]. Although the present resonant strength for He-like iodine ion is less than the experimental result [3], it is coincides with the variation of theoretical calculations for other He-like ions along with Z.…”

“…2, for elements heavier than Ar, the resonant strengths become smaller with increasing Z, since . The other data are Ar 16+ [20], Ti 20+ [2], Fe 24+ [21], Ni 26+ , Mo 40+ , and Ba 54+ [22], Ge 30+ [7], Kr 34+ [23], I 51+ [3], Hg 78+ and U 90+ [11]. electron capture into doubly excited states becomes more difficult as Z increases.…”

“…The DR of such heavy ions is one of the primary sources of radiative energy loss from fusion plasmas and can lead to plasma cooling and thus the understanding of the DR process is important for controlling such energy-loss. At resonant energies, the DR cross sections are several orders of magnitude larger than those of the other processes in charge state equilibrium plasmas [7]. Thus, data production of DR is both important and imperative in plasma physics.…”

Leaky ion extraction method for dielectronic recombination strength measurements at electron-beam ion traps

“…In high-Z ions with few electrons, higher electron-ion collision energies * Zouym@fudan.edu.cn are needed for n > 0 DR processes, especially for those involving K-shell electron excitation. EBIT and EBIS are commonly employed in these cases [10][11][12][13][14][15][16][17][18][19][20][21][22].…”

State-selective quantum interference observed in the photorecombination of ions at the Heidelberg EBIT

“…The Heidelberg EBIT (Crespo Lo´pez Urrutia et al, 1999) (see Fig. 2) has a dedicated setup for the study of photorecombination, which has already been used e.g., to study the effect of the two-electron-one-photon transition in the dielectronic resonances of He-like Ar 16þ (Zou et al, 2003) and the dielectronic resonances of Ge 30þ (Zhang et al, 2004). This apparatus has recently been improved for precision experiments at higher energies.…”