Query : 2010A&A...513A..55C

2010A&A...513A..55C - Astronomy and Astrophysics, volume 513, A55-55 (2010/4-1)

Electron-impact excitation of Ni II. Collision strengths and effective collision strengths for low-lying fine-structure forbidden transitions.


Abstract (from CDS):

Considerable demand exists for electron excitation data for NiII, since lines from this abundant ion are observed in a wide variety of laboratory and astrophysical spectra. The accurate theoretical determination of these data can present a significant challenge however, due to complications arising from the presence of an open 3d-shell in the description of the target ion. In this work we present collision strengths and Maxwellian averaged effective collision strengths for the electron-impact excitation of NiII. Attention is concentrated on the 153 forbidden fine-structure transitions between the energetically lowest 18 levels of NiII. Effective collision strengths have been evaluated at 27 individual electron temperatures ranging from 30-100000K. To our knowledge this is the most extensive theoretical collisional study carried out on this ion to date. The parallel R-matrix package RMATRX II has recently been extended to allow for the inclusion of relativistic effects. This suite of codes has been utilised in the present work in conjunction with PSTGF to evaluate collision strengths and effective collision strengths for all of the low-lying forbidden fine-structure transitions. The following basis configurations were included in the target model - 3d9, 3d84s, 3d84p, 3d74s2 and 3d74s4p - giving rise to a sophisticated 295 jj-level, 1930 coupled channel scattering problem. Comprehensive comparisons are made between the present collisional data and those obtained from earlier theoretical evaluations. While the effective collision strengths agree well for some transitions, significant discrepancies exist for others.

Abstract Copyright:

Journal keyword(s): atomic data - atomic processes - scattering - plasmas - methods: numerical - binaries: symbiotic

VizieR on-line data: <Available at CDS (J/A+A/513/A55): table1.dat table2.dat csdata/*>

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 IRAS 07598+6508 Sy1 08 04 30.4643108040 +64 59 52.789588188   14.3 15.5     ~ 218 0
2 * eta Car Em* 10 45 03.5377808928 -59 41 04.051599720 6.37 7.03 6.48 4.90 4.41 OBepec 2326 0
3 GRB 060418 gB 15 45 42.600 -03 38 20.00 15.73 16.19 14.98     ~ 341 0

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