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Multipole cross sections for collisional excitation of highly charged ions by isotropic electrons
Author(s) -
Bentotoche Mohamed Sadek,
Inal Mokhtar Kemal,
Benmouna Mustapha
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.3054
Subject(s) - excitation , atomic physics , multipole expansion , physics , electron , collisional excitation , isotropy , ion , electron excitation , plasma , polarization (electrochemistry) , computational physics , chemistry , optics , nuclear physics , quantum mechanics , ionization
The relativistic distorted‐wave program of the flexible atomic code for calculating the cross sections for electron‐impact excitation of ions between fine‐structure levels is extended to get the multipole components of cross sections in the case of excitation by isotropic electrons. These components may be needed for interpreting the intensity and polarization of line emissions from thermal plasmas exposed to anisotropic radiations, such as the solar corona under photosphere irradiation. Illustrative numerical results are given for excitation of Si‐like Fe 12+ between the 3 s 2 3 p 23 P 1 ,3 P 2 and1 D 2 levels. These results can be useful in the analysis of infrared forbidden lines emitted from the solar corona. A comparison is made with the only published work based on the semi‐relativistic distorted‐wave approximation, showing some agreement for the excitation3 P 1 →3 P 2 and discrepancies for the weak transition3 P 1 →1 D 2 .