The CHIANTI database consists of the following primary ASCII files for this ion:

si_2.elvlc (energy levels)

contains the energy levels in cm^(-1) It includes both experimental and theoretical values of the levels energies.

 
%observed energy levels: Martin, W.C., Sugar, J., Musgrove, A., Dalton, G.R., 1995,
   NIST Database for Atomic Spectroscopy, Version 1.0, NIST Standard Reference Database 61
%theoretical energy levels: P.R.Young (DAMTP, Un. of Cambridge, UK), SUPERSTRUCTURE calculations, 1996
% produced as part of the Arcetri/Cambridge/NRL 'CHIANTI' atomic data base collaboration
%
%   E. Landi 1996
 

si_2.wgfa (radiative data)

contains wavelengths, gf and A values of the transitions. The wavelengths are based on the experimental energy levels and should be the best available. Wavelengths calculated from the theoretical energies are of an indeterminate accuracy and their values are presented as negative values of the calculated wavelength.

 
%filename: si_2.wgfa
%observed energy levels: Martin, W.C., Sugar, J., Musgrove, A., Dalton, G.R., 1995,
   NIST Database for Atomic Spectroscopy, Version 1.0, NIST Standard Reference Database 61
%A-values, gf-values: Nahar S.N., 1998, ADNDT 68, 183
%A-values, gf-values: Nussbaumer H., 1977, A&A 58, 291
%comment: The Nussbaumer A-values are used for the transitions between levels 
   1 to 5, i.e., the forbidden and intercombination transitions. Nahar 
   did not calculate A-values for these transitions.

   Nahar only gave gf values. These were converted to A-values by using 
   the experimental energy separation.

   Table A of Nahar gives a useful comparison of his gf values with 
   those from previous calculations and experiment.
%comment: correction on 11-Jun-03, Peter Young
   The 1-3 A-value was incorrectly listed as 4.550E-03. The correct value 
   of 4.550E+03 has now been inserted. It affects line at 2335 A (Error spotted 
   by Sergei Lamzin.)
% produced as part of the Arcetri/Cambridge/NRL 'CHIANTI' atomic data base collaboration
%
%   P.R.Young - Jun 2003

si_2.splups (electron collision data)

contains the spline fits to the electron collision strengths scaled according the rules formulated by Burgess and Tully (1992). Accurate replication of the temperature averaged collision strength over a wide range of temperatures can be accomplished with the data in this file.

 

%filename: si_2.splups
%oscillator strengths: Nahar S.N., 1998, ADNDT 68, 183
%oscillator strengths: Nussbaumer H., 1977, A&A 58, 291
%effective collision strengths: Dufton,P.L., Kingston,A.E., 1991, MNRAS, 248, 827
%comment: effective collision strengths were provided in the temperature range 3.6 < Log T < 4.6
%produced as part of the Arcetri/Cambridge/NRL 'CHIANTI' atomic data base collaboration
%
% Enrico Landi - 1996

si_2.psplups (proton collision data)

contains the spline fits to the scaled proton collision strengths.

 

%filename: si_2.psplups
%rates: Bely, O., Faucher, P., 1970, A&A 6, 88
%energies: Observed energies from .elvlc file.
%produced as part of the Arcetri/Cambridge/NRL 'CHIANTI' atomic data base collaboration
%
% Peter Young   8-Jun-2001

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The html table below contains the radiative data of the brightest lines sorted in wavelength

si_2_table.html (html table)


Last revised by G. Del Zanna on 4-Sep-2009