<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Hoszowska, Joanna</dc:creator>
  <dc:creator>Dousse, Jean-Claude</dc:creator>
  <dc:date>2012-09-12</dc:date>
  <dc:description xmlns:ns0="xml" ns0:lang="en">The mechanisms leading to the production of hollow &lt;em&gt;K&lt;/em&gt; shell atoms via single photon impact were investigated for a variety of light elements with 12 ≤ &lt;em&gt;Z&lt;/em&gt; ≤ 23. The double 1&lt;em&gt;s&lt;/em&gt; vacancy states were produced by irradiating the samples with intense monoenergetic synchrotron radiation beams. The double-to-single &lt;em&gt;K&lt;/em&gt;-shell photoionization probabilities &lt;em&gt;P&lt;/em&gt;&lt;sub&gt;&lt;em&gt;KK&lt;/em&gt;&lt;/sub&gt; and the absolute double &lt;em&gt;K&lt;/em&gt;-shell photoionization cross sections &lt;em&gt;σ&lt;/em&gt;²⁺ were determined by measuring with a high-resolution bent von Hamos crystal spectrometer the &lt;em&gt;Kα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt; hypersatellite X-ray emission of the samples. The measurements were performed over a wide range of incoming photon energies from threshold up to energies beyond the broad maximum of the double-to-single photoionization cross section ratios. The &lt;em&gt;P&lt;/em&gt;&lt;sub&gt;&lt;em&gt;KK&lt;/em&gt;&lt;/sub&gt; and &lt;em&gt;σ&lt;/em&gt;²⁺ were determined from the relative yields of the resolved &lt;em&gt;Kα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt; hypersatellite lines. For Mg, Al and Si, the two-electron one-photon (TEOP) &lt;em&gt;Kαα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt; transitions which represent an alternative but much weaker decay channel for double 1&lt;em&gt;s&lt;/em&gt; vacancy states could be also observed, using a highly efficient flat crystal wavelength dispersive spectrometer. This observation of single photon-induced TEOP transitions has shown that the &lt;em&gt;I&lt;/em&gt;(&lt;em&gt;Kα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt;)/&lt;em&gt;I&lt;/em&gt;(&lt;em&gt;Kαα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt;) branching ratios are very poorly reproduced by most of existing theoretical models. Besides the relative yields of the hypersatellite and TEOP transitions, the energies and natural linewidths of the &lt;em&gt;Kα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt; and &lt;em&gt;Kαα&lt;/em&gt;&lt;sup&gt;&lt;em&gt;h&lt;/em&gt;&lt;/sup&gt; X-ray lines were also determined. The energies are found to be in good agreement with different theoretical predictions, whereas the linewidths are significantly underestimated by the calculations, except if non-lifetime broadening effects such as the outer-shell ionization and the open valence configuration are taken into consideration.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>https://folia.unifr.ch/global/documents/302639</dc:identifier>
  <dc:identifier>https://folia.unifr.ch/documents/302639/files/dou_pkh.pdf</dc:identifier>
  <dc:language>eng</dc:language>
  <dc:relation>info:eu-repo/semantics/altIdentifier/doi/10.1016/j.elspec.2012.09.001</dc:relation>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>License undefined</dc:rights>
  <dc:source>Journal of Electron Spectroscopy and Related Phenomena. - 2013, vol. 188, p. 62-70</dc:source>
  <dc:subject xmlns:ns1="xml" ns1:lang="en">Double K shell photoionization</dc:subject>
  <dc:subject xmlns:ns2="xml" ns2:lang="en">Multi core electron correlated processes</dc:subject>
  <dc:subject xmlns:ns3="xml" ns3:lang="en">High resolution X ray spectroscopy</dc:subject>
  <dc:subject xmlns:ns4="xml" ns4:lang="en">Synchrotron radiation</dc:subject>
  <dc:subject>info:eu-repo/classification/udc/53</dc:subject>
  <dc:title xmlns:ns5="xml" ns5:lang="en">Photoinduced K-shell hollow atoms</dc:title>
  <dc:type>http://purl.org/coar/resource_type/c_6501</dc:type>
</oai_dc:dc>