Multiple ionization and coupling effects in L-subshell ionization of heavy atoms by oxygen ions

Journal Article · Fri Aug 01 00:00:00 EDT 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.68.022705· OSTI ID:20640058

Pajek, M; Banas, D; Semaniak, J; Braziewicz, J; Majewska, U; Chojnacki, S; Czyzewski, T; Fijal, I; Jaskola, M; Glombik, A; Kretschmer, W; Trautmann, D; Lapicki, G; Mukoyama, T ^[1]

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1. Institute of Physics, Swietokrzyska Academy, 25-406 Kielce, (Poland)

The multiple-ionization and coupling effects in L-shell ionization of atoms by heavy-ion impact have been studied by measuring the L x-ray production cross sections in solid targets of Au, Bi, Th, and U bombarded by oxygen ions in the energy range 6.4-70 MeV. The measured L x-ray spectra were analyzed using the recently proposed method accounting for the multiple-ionization effects, such as x-ray line shifting and broadening, which enables one to obtain the ionization probabilities for outer shells. The L-subshell ionization cross sections have been obtained from measured x-ray production cross sections for resolved L{alpha}{sub 1,2}, L{gamma}{sub 1}, and L{gamma}{sub 2,3} transitions using the L-shell fluorescence and Coster-Kronig yields being substantially modified by the multiple ionization in the M and N shells. In particular, the effect of closing of strong L{sub 1}-L{sub 3}M{sub 4,5} Coster-Kronig transitions in multiple-ionized atoms was evidenced and discussed. The experimental ionization cross sections for the L{sub 1}, L{sub 2}, and L{sub 3} subshells have been compared with the predictions of the semiclassical approximation (SCA) and the ECPSSR theory that includes the corrections for the binding-polarization effect within the perturbed stationary states approximation, the projecticle energy loss, and Coulomb deflection effects as well as the relativistic description of inner-shell electrons. These approaches were further modified to include the L-subshell couplings within the ''coupled-subshell model'' (CSM). Both approaches, when modified for the coupling effects, are in better agreement with the data. Particularly, the predictions of the SCA-CSM calculations reproduce the experimental L-subshell ionization cross section reasonably well. Remaining discrepancies are discussed qualitatively, in terms of further modifications of the L-shell decay rates caused by a change of electronic wave functions in multiple-ionized atoms.

• OSTI ID: 20640058
• Journal Information: Physical Review. A, Vol. 68, Issue 2; Other Information: DOI: 10.1103/PhysRevA.68.022705; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
CORRECTIONS
COSTER-KRONIG TRANSITIONS
COUPLING
CROSS SECTIONS
ELECTRONS
EMISSION SPECTRA
ENERGY LOSSES
FLUORESCENCE
HEAVY IONS
ION-ATOM COLLISIONS
IONIZATION
L SHELL
LINE BROADENING
MEV RANGE
N SHELL
OXYGEN IONS
POLARIZATION
RELATIVISTIC RANGE
SEMICLASSICAL APPROXIMATION
SPECTRAL SHIFT
WAVE FUNCTIONS
X RADIATION
X-RAY SPECTRA