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Title: Channels of Potential Energy Dissipation during Multiply Charged Argon-Ion Bombardment of Copper

Abstract

The dissipation of potential energy of multiply charged Ar ions incident on Cu has been studied by complementary electron spectroscopy and calorimetry at charge states between 2 and 10 and kinetic energies between 100 eV and 1 keV. The emitted and deposited fractions of potential energy increase at increasing charge state, showing a significant jump for charge states q>8 due to the presence of L-shell vacancies in the ion. Both fractions balance the total potential energy, thus rendering former hypotheses of a significant deficit of potential energy obsolete. The experimental data are reproduced by computer simulations based on the extended dynamic classical-over-the-barrier model.

Authors:
; ; ; ;  [1];  [2]
  1. Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
20951454
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 22; Other Information: DOI: 10.1103/PhysRevLett.98.225503; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ARGON IONS; CALORIMETRY; CHARGE STATES; COMPUTERIZED SIMULATION; COPPER; ELECTRON SPECTROSCOPY; EV RANGE 100-1000; EXPERIMENTAL DATA; ION BEAMS; KINETIC ENERGY; L SHELL; MULTICHARGED IONS; POTENTIAL ENERGY; VACANCIES

Citation Formats

Kost, D., Facsko, S., Moeller, W., Hellhammer, R., Stolterfoht, N., and Division of Structure Research, Hahn-Meitner Institute, 14109 Berlin. Channels of Potential Energy Dissipation during Multiply Charged Argon-Ion Bombardment of Copper. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.225503.
Kost, D., Facsko, S., Moeller, W., Hellhammer, R., Stolterfoht, N., & Division of Structure Research, Hahn-Meitner Institute, 14109 Berlin. Channels of Potential Energy Dissipation during Multiply Charged Argon-Ion Bombardment of Copper. United States. doi:10.1103/PHYSREVLETT.98.225503.
Kost, D., Facsko, S., Moeller, W., Hellhammer, R., Stolterfoht, N., and Division of Structure Research, Hahn-Meitner Institute, 14109 Berlin. Fri . "Channels of Potential Energy Dissipation during Multiply Charged Argon-Ion Bombardment of Copper". United States. doi:10.1103/PHYSREVLETT.98.225503.
@article{osti_20951454,
title = {Channels of Potential Energy Dissipation during Multiply Charged Argon-Ion Bombardment of Copper},
author = {Kost, D. and Facsko, S. and Moeller, W. and Hellhammer, R. and Stolterfoht, N. and Division of Structure Research, Hahn-Meitner Institute, 14109 Berlin},
abstractNote = {The dissipation of potential energy of multiply charged Ar ions incident on Cu has been studied by complementary electron spectroscopy and calorimetry at charge states between 2 and 10 and kinetic energies between 100 eV and 1 keV. The emitted and deposited fractions of potential energy increase at increasing charge state, showing a significant jump for charge states q>8 due to the presence of L-shell vacancies in the ion. Both fractions balance the total potential energy, thus rendering former hypotheses of a significant deficit of potential energy obsolete. The experimental data are reproduced by computer simulations based on the extended dynamic classical-over-the-barrier model.},
doi = {10.1103/PHYSREVLETT.98.225503},
journal = {Physical Review Letters},
number = 22,
volume = 98,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}
  • The retained fraction of the potential energy of argon ions incident on copper has been measured using stationary calorimetry at charge states up to 9+ and kinetic energies ranging from 75 to 240eV per ionic charge. An average fraction of 30% to 40% is found with little dependence on the charge number and on the kinetic energy. The retention of the total energy ranges from 60% to 75% and can mainly be accounted for by the retained fraction of the potential energy and the collisional energy lost by reflected ions and sputtered target atoms.
  • X-ray emission yields from highly charged iodine ions incident on a hydrogen terminated silicon surface were measured. It was found that the K shell vacancies were filled through x-ray transitions with the probability of approximately 100%, while only about 20% of L shell vacancies were filled through x-ray transitions and almost all the M shell vacancies were filled nonradiatively. Dissipation of the potential energy E{sub p} of an incident ion through x-ray emissions increases gradually with the number of L shell vacancies and amounts to 10% of E{sub p} for the He-like I{sup 51+} ion. 30 to 40 % ofmore » E{sub p} for I{sup 52+} and I{sup 53+} with K shell vacancies was measured to be dissipated mainly by K x-ray emissions.« less
  • Quenching rates have been measured for selected metastable levels of Ar[sup [ital q]+] ions ([ital q]=2, 3, 9, and 10) stored in a Kingdon ion trap, with mean energies of 262[ital q] eV and 181[ital q] eV. Effective quenching cross sections derived from these rates are found to be comparable to electron-capture cross sections of Ar[sup [ital q]+]-Ar collisions studied independently using ion-beam techniques. This implies that quenching is dominated by electron-capture collisions which change the ion charge state.
  • Cross sections sigma/sub i//sub f/ for electron capture processes of up to four electrons in single ion--atom encounters of multiply charged argon ions (up to Ar/sup 7 +/) in nitrogen and krypton targets are measured. The cross sections show no significant energy dependence in the investigated energy range from 10 to 110 keV. A plot of the cross sections for nitrogen and krypton target gases vs the projectiles initial charge state number i reveals a structure which is very similar to the structure previously reported for argon. (AIP)