L-shell ionization in near-central collisions of heavy ions with low-Z atoms

M. Kavčič, M. Budnar, A. Mühleisen, P. Pelicon, Šmit, M. Žitnik, D. Castella, D. Corminboeuf, J. Cl Dousse, J. Hoszowska, P. A. Raboud, K. Tőkési

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The [Formula Presented] x-ray emission spectra of Ca, Ti, Cr, and Fe targets bombarded by 2–19-MeV/amu C, O, and Ne ions were measured by means of high-resolution crystal diffractometry. The [Formula Presented] x-ray satellite lines appearing in these spectra as a result of the radiative decay of atomic states with one hole in the K shell and N in the L subshells could be resolved, and their relative intensities determined. The latter were corrected to account for the intra-atomic rearrangement processes preceding the K x-ray emission. From the values obtained the heavy ion induced L-shell vacancy distribution was then deduced for each collision. Significant deviations from the binomial distribution were observed. The discrepancies could be slightly diminished by assuming that the L-shell vacancy production is due to two uncorrelated processes: direct Coulomb ionization and target L-shell electron capture into the projectile K shell. A new [Formula Presented] vacancy yield distribution model based on statistical considerations was built, which takes into account both mechanisms of vacancy production. The average direct L-shell ionization probabilities per electron related to the investigated collisions were determined by fitting this distribution to the corrected experimental L vacancy yields, employing results of three-body classical trajectory Monte Carlo (CTMC) calculations for the electron capture probabilities. The so-obtained direct ionization probabilities were found to be somewhat smaller than the ones deduced from the standard binomial distribution, especially in low-energy collisions for which electron capture is more important. It was furthermore observed that CTMC calculations significantly overestimate the direct ionization probabilities found in the present experiment. To a smaller extent, the same holds for the geometrical model predictions, whereas theoretical results from the semiclassical approximation model were found to reproduce the experimental data better.

Original languageEnglish
Number of pages1
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number5
Publication statusPublished - Jan 1 2000


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Kavčič, M., Budnar, M., Mühleisen, A., Pelicon, P., Šmit, Žitnik, M., Castella, D., Corminboeuf, D., Dousse, J. C., Hoszowska, J., Raboud, P. A., & Tőkési, K. (2000). L-shell ionization in near-central collisions of heavy ions with low-Z atoms. Physical Review A - Atomic, Molecular, and Optical Physics, 61(5). https://doi.org/10.1103/PhysRevA.61.052711