Polarized light emission in keV He2++Na(3s) collisions

S. Schippers*, P. Boduch, J. Van Buchem, F. W. Bliek, R. Hoekstra, R. Morgenstern, R. E. Olson

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

We investigated l and m-distributions of He II (n = 4) states formed during 2-13.3 keV amu(-1) He2+ + Na(3s) collisions by measuring profiles and the linear polarization of the He II (4 --> 3) emission. We found that at these energies capture into He+(4f) dominates over capture into other He+(4l) states. Over the indicated energy range the polarization of the He-4 II (4 --> 3) photon emission increases from 0.2 to 0.3 indicating a strong alignment of the captured projectile charge cloud along the internuclear axis. Due to the non-zero nuclear spin the polarization is up to 10% lower when using He-3(2+) projectiles instead of He-4(2+). Classical trajectory Monte Carlo calculations agree quantitatively with these experimental findings and predict a decrease of the polarization towards zero at higher energies due to enhanced capture into He+(4s).

A positive polarization is also found for the Na I (3p --> 3s) target de-excitation. However, due to strong depolarization effects caused by the nuclear spin of the Na-23 nucleus it stays below 0.14.

Original languageEnglish
Pages (from-to)3271-3282
Number of pages12
JournalJournal of Physics B-Atomic Molecular and Optical Physics
Volume28
Issue number15
DOIs
Publication statusPublished - 14-Aug-1995

Keywords

  • ELECTRON-CAPTURE
  • EXCITATION
  • STATE
  • ALIGNMENT
  • IMPACT
  • IONS
  • H-2

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