Xenon photoionization in the vicinity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>4</mml:mn><mml:mi>d</mml:mi></mml:mrow></mml:math> giant resonance and Cooper minimum using an XUV-NIR pump-probe experiment

The relaxation processes in atomic xenon following core ionization of the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>4</a:mn><a:mi>d</a:mi></a:mrow></a:math> and <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mn>4</b:mn><b:mi>p</b:mi></b:mrow></b:math> subshells by extreme ultraviolet (XUV) pulses from a free-electron laser (FLASH) are investigated using ion time-of-flight spectroscopy. We compare the dynamics following ionization and Auger-Meitner decays at 90-eV photon energy, i.e., near the giant resonance, with those at 160 eV, near the Cooper minimum, where cross sections for photoionization of the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>4</c:mn><c:mi>d</c:mi></c:mrow></c:math> and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mn>4</d:mn><d:mi>p</d:mi></d:mrow></d:math> subshells are similar. Final states with charges higher than 4 show signatures of sequential absorption of two XUV photons, followed by subsequent Auger-Meitner decay. The averaged lifetimes of some important excited states are measured in a two-color XUV-pump–near-infrared-probe experiment. A transient enhancement in the ion yield of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:msup><e:mrow><e:mi>Xe</e:mi></e:mrow><e:mrow><e:mn>5</e:mn><e:mo>+</e:mo></e:mrow></e:msup></e:math> with an average lifetime of <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mo>(</f:mo><f:mn>49</f:mn><f:mo>±</f:mo><f:mn>3</f:mn><f:mo>)</f:mo></f:mrow></f:math> fs is obtained, attributed to transient intermediate states following the decay of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mrow><g:mn>4</g:mn><g:mi>d</g:mi></g:mrow></g:math> double-core-hole states. Published by the American Physical Society 2024