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Population of the 1 s 2 s ( 3 S ) n l 2 L states in collisions of mixed‐state (1 s 2 1 S ,1 s 2 s 3 S ) B 3+ and C 4+ ion beams with He and H 2 targets
Author(s) -
Benis Emmanouil P.,
Madesis Ioannis,
Laoutaris Angelos,
Nikolaou Sofoklis,
Dubois Alain,
Gorczyca Tom W.,
Zouros Theo J. M.
Publication year - 2019
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.3050
Subject(s) - atomic physics , excited state , spectral line , physics , electron , population , auger electron spectroscopy , electron capture , state (computer science) , chemistry , nuclear physics , quantum mechanics , demography , algorithm , sociology , computer science
Auger KLn lines are observed in high‐resolution electron spectra obtained in collisions of mixed‐state (1 s 2 1 S ,1 s 2 s 3 S ) He‐like beams of 4 MeV B 3+ with H 2 and 6 MeV C 4+ with He targets. Supporting atomic structure calculations show these lines to correspond to 1 s 2 s ( 3 S ) n l2 L doubly excited states, which can be readily populated by electron transfer to the 1 s 2 s3 S component of the mixed‐state beam. They thus provide indirect evidence for the existence of the corresponding 1 s 2 s ( 3 S ) n l4 L KLn quartet states, similarly produced, even though their weak Auger decay does not allow for their direct observation in the electron spectra. These KLn quartet states mostly decay in a cascade chain of strong radiative E 1 transitions, eventually terminating at the 1 s 2 s 2 p4 P state, which is thus additionally enhanced. An upper limit on the 1 s 2 s 2 p4 P state population due to cascades is obtained by assuming a statistical production of KLn quartet to doublet states followed by a 100% cascade feeding of the 1 s 2 s 2 p4 P state. Our estimated upper limit is supported by our absolute cross section measurements and corresponding three‐electron atomic orbital close coupling calculations in progress. Results to date are presented and discussed.