Disentangling Auger decays in O₂ by photoelectron-ion coincidences
|Author:||Liu, Xiao-Jing1,2; Nicolas, Christophe2; Patanen, Minna2,3;|
1School of Physics and Nuclear Energy Engineering, Beihang University, Beijing, 100191, China
2Synchrotron SOLEIL, l’Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif-sur-Yvette Cedex, France
3Nano and Molecular Systems Research Unit, Molecular Materials Research Community, Faculty of Science, University of Oulu, P.O. Box 3000, 90014, Oulu, Finland
4Extreme Light Infrastructure Nuclear Physics (ELI-NP), “Horia Hulubei” National Institute for Physics and Nuclear Engineering, 30 Reactorului Street, RO-077125, Măgurele, Jud. Ilfov, Romania
|Online Access:||PDF Full Text (PDF, 2.2 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe201804036298
|Publish Date:|| 2018-04-03
In non-resonant Auger electron spectroscopies, multi core-ionized states lead to numerous energetically close-lying electronic transitions in Auger spectra, this hampering the assignment and interpretation of the experimental results. Here we reveal a new method to overcome this intrinsic limitation of non-resonant inner-shell spectroscopies. In a proof-of-principle experiment performed for the O₂ molecule, most of the Auger final states are dissociative, and we measure in coincidence the kinetic energy of the photoelectron and the kinetic energy release of the (O⁺, O⁺) ion pairs produced after the Auger decay of the O 1s−1 core-ionized states. The Auger final states are assigned using energy conservation. We fully separate the contributions from the ⁴Σ− and ²Σ− intermediate ionic states and conclusively demonstrate that the Auger decay probability can dramatically depend on the different O₂ 1s−1 intermediate multiplet states. In addition, a metastable Auger final state also exists, with lifetime longer than 3.8 μs, and clear changes are observed in both branching ratio and spectral profile of the O 1s photoelectron spectrum when they are recorded in coincidence with either O₂⁺⁺ or with other ionic species. These changes are attributed to the population of the metastable B′³Σ−u(ν′′=0) Auger final state via different intermediate states.
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
114 Physical sciences
X.L. gratefully acknowledges the financial support by the National Natural Science Foundation of China (11574020) and Project of Thousand Youth Talents in China.
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