1. |
- Dias, E.W.B, et al.
(author)
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Breakdown of the independent particle approximation in high-energy photoionization
- 1997
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In: Physical Review Letters. - 0031-9007. ; 78:24, s. 4553-4556
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Journal article (peer-reviewed)abstract
- The independent particle approximation is shown to break down for the photoionization of both inner and outer nl (l > 0) electrons of all atoms, at high enough energy, owing to interchannel interactions with the nearby ns photoionization channels. The effect is illustrated for Ne 2p in the 1 keV photon energy range through a comparison of theory and experiment. The implications for x-ray photoelectron spectroscopy of molecules and condensed matter are discussed.
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2. |
- Hemmers, O, et al.
(author)
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Beyond the dipole approximation: angular-distribution effects in valence photoemission
- 1997
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In: Journal of Physics B: Atomic, Molecular and Optical Physics. - 0953-4075. ; 30:21, s. L727-L733
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Journal article (peer-reviewed)abstract
- Angular distributions of valence photoelectrons showing effects due to highermultipole photon interactions have been measured for the first time. Neon 2s and 2p photoemission exhibits effects beyond the dipole approximation throughout the 250 to 1200 eV photon-energy range studied. The results suggest that any photoemission experiment, on any sample, can be affected at relatively low photon energies, pointing to a general need for caution in interpreting angle-resolved-photoemission measurements.
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4. |
- Wehlitz, R, et al.
(author)
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Photon energy dependence of ionization-excitation in helium at medium energies
- 1997
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In: Journal of Physics B: Atomic, Molecular and Optical Physics. - 0953-4075. ; 30:2, s. L51-L58
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Journal article (peer-reviewed)abstract
- We have measured the photoionization-excitation-to-photoionization ratio for He(+)nl (n = 2-6) at several photon energies from 90 to 900 eV. By extrapolating these values we could determine the asymptotic high-energy ratios for He(+)nl (n = 2-5) which agree with theoretical predictions. We show that the satellite-to-main-line ratios are consistent with experimental double-to-single photoionization ratios and agree well with recent measurements.
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