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Highly charged ion
About: Highly charged ion is a research topic. Over the lifetime, 609 publications have been published within this topic receiving 6002 citations.
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251 citations
TL;DR: In this article, the authors compared the predictions of a simple point charge model with and without corrections for polarization and repulsion for the removal of various electrons from the alkali chlorides and the sodium and cesium halides.
Abstract: We have measured ionization potentials for the removal of various electrons from the alkali chlorides and the sodium and cesium halides. These binding energies are compared with the predictions of a simple point charge model with and without corrections for polarization and repulsion. The simple model predicts and the data show that the spacings of the energy levels for a given ion are independent of what crystal it is in and are the same as for the free ion. The point charge model also allows us to calculate the difference between cation and anion energy levels in the same crystal. There is, however, a disagreement between the predicted and experimental values of this difference that ranges from about 1.8 eV for LiCl to −0.2 eV for RbCl. This discrepancy is markedly reduced by inclusion of polarization effects. The point charge model with polarization and repulsion corrections predicts absolute ionization potentials for the alkali and halide ions that differ in a systematic way from those observed. For the sodium halides, the difference between calculated and experimental energies decreases monotonically from about −4 eV for NaF to about 0.9 eV for NaI. The origin of these discrepancies is apparently due to charging of the samples and their trend is directly attributable to the size of the respective bandgaps. We show that the electrostatic model can be used to provide a comparison between experimental binding energies for inner electrons in a crystal and Hartree‐Fock calculations for binding energies of inner electrons in free atoms. Finally, using the point charge model we show that the binding energy of an electron on a highly charged ion in an ionic crystal is only slightly different from the binding energy of the same electron in the neutral atom.
169 citations
TL;DR: The ability of freestanding single layer graphene to provide tens of electrons for charge neutralization of a slow highly charged ion within a few femtoseconds is reported on and time-dependent density functional theory is used to gain insight into the multielectron dynamics.
Abstract: The way conduction electrons respond to ultrafast external perturbations in low dimensional materials is at the core of the design of future devices for (opto)electronics, photodetection and spintronics. Highly charged ions provide a tool for probing the electronic response of solids to extremely strong electric fields localized down to nanometre-sized areas. With ion transmission times in the order of femtoseconds, we can directly probe the local electronic dynamics of an ultrathin foil on this timescale. Here we report on the ability of freestanding single layer graphene to provide tens of electrons for charge neutralization of a slow highly charged ion within a few femtoseconds. With values higher than 1012 A cm−2, the resulting local current density in graphene exceeds previously measured breakdown currents by three orders of magnitude. Surprisingly, the passing ion does not tear nanometre-sized holes into the single layer graphene. We use time-dependent density functional theory to gain insight into the multielectron dynamics. Graphene has so far demonstrated remarkable properties, making it increasingly interesting for ultrafast electronic applications. Here, the authors show that, when probed by a highly charged ion, freestanding graphene is able to provide dozens of electrons for ion neutralization within a few femtoseconds.
135 citations
TL;DR: In this paper, the authors investigated the properties of an electron beam ion trap (EBIT) after the electron beam is switched off, and showed that the ion storage time in this mode depends on the pressure of background atoms as well as on the value of the externally applied trapping potential.
Abstract: Using x‐ray spectroscopic techniques, we have investigated the properties of an electron beam ion trap (EBIT) after the electron beam is switched off. In the absence of the electron beam, bare, and hydrogenlike Kr35+ and Kr36+ ions remain trapped due to externally applied magnetic and electric fields for at least 5 s; xenon ions with an open L shell, i.e., Xe45+–Xe52+, remain trapped at least as long as 20 s. The ion storage time in this ‘‘magnetic trapping mode’’ depends on the pressure of background atoms as well as on the value of the externally applied trapping potential, and even longer ion storage times appear possible. The magnetic trapping mode enables a variety of new opportunities for atomic physics research involving highly charged ions, which include the study of charge transfer reactions, Doppler‐shift‐free measurements of the Lamb shift, measurements of radiative lifetimes of long‐lived metastable levels, or ion‐ion collision studies, by x‐ray or laser spectroscopy, and mass spectrometry. Be...
105 citations
TL;DR: In this article, the absolute ion densities in an electron-cyclotron-resonance ion source (ECRIS) plasma have been measured using high-resolution x-ray spectroscopy of emission lines from highly charged argon ions.
Abstract: Absolute ion densities in an electron-cyclotron-resonance ion source (ECRIS) plasma have been measured using high-resolution x-ray spectroscopy of $(n=2)\ensuremath{\rightarrow}(n=1)$ emission lines from highly charged argon ions. Ion densities have been correlated to extracted currents. The evolution of the ion confinement times with charge state has been investigated for various plasma parameters: a linear increase of the confinement time with charge was found. This result leads to a better understanding of the ion confinement mechanism in ECRIS plasmas.
88 citations