Hannover 2016 – scientific programme
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A: Fachverband Atomphysik
A 22: Interaction with VUV and X-ray light
A 22.12: Poster
Tuesday, March 1, 2016, 16:30–19:00, Empore Lichthof
Observation of four-electron Auger processes — A. Müller1, A. Borovik Jr.1, T. Buhr2, J. Hellhund1, K. Holste1, A. L. D. Kilcoyne3, S. Klumpp4, M. Martins4, S. Ricz5, J. Viefhaus6, and •S. Schippers1 — 1Justus-Liebig-Universität Gießen — 2PTB, Braunschweig — 3Lawrence Berkeley National Laboratory, USA — 4Universität Hamburg — 5ATOMKI, Debrecen, Hungary — 6FS-PE, DESY, Hamburg
We report on the observation of triple-Auger decay processes [1] in which C+(1s2s22p2 2D,2P) terms were selectively excited by irradiating singly charged carbon ions by VUV photons at the PETRA III synchrotron light source. Subsequent to the decay of the intermediate resonantly excited K-vacancy terms, product ions C2+, C3+ and C4+ were recorded. Absolute cross sections for processes γ + C+(1s22s22p 2P) → C+(1s2s22p2 2D,2P) → C1+m+(1s22ℓ3−m)+ me leading to net photoionization with m=1,2,3 were determined. In addition, the natural linewidths of the intermediate resonant states could be measured. By combining all this information, the absolute transition rates for radiative as well as single and multiple Auger decays were inferred. The triple-Auger decay rate was found to be 2.0× 1010 s−1 for the C+(1s2s22p2 2D) and 9.7× 109 s−1 for the C+(1s2s22p2 2P) intermediate resonantly-excited terms investigated in this study. The ratios of single- to double- to triple-Auger rates of the 2D and 2P terms are about 100 : 2.7 : 0.013 and 100 : 3.3 : 0.013, respectively.
A. Müller et al., Phys. Rev. Lett. 114 (2015) 013002.