qcx#h0_en2_kvi#he2.dat

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  Source:  The data consists of results of CTMC calculations made at the University of Missouri over 
              the period 1995-97.
     
  Comments:  At this time, no direct comparison with other results is available for checking the 
             quality of the nl selective cross-sections except for Li+3 for which results are given
             in a recent hidden curve crossing calculation by Janev et al. (1996).  Large differences
             are observed in both the magnitude and energy dependence.  From inspection of the total
             cross-sections, we have the strong impression that the CTMC data should be preferred.
             In a plot of the scaled total one-electron capture cross-sections (sigma_tot(16q)^-1)
             versus scaled energy (4Eq^-1/2), the total cross-sections should be approximately the
             same for all systems (Janev, 1991) at least for q>3.  In these scaled units, a 
             recommendation by Janev and Smith (1995) has been presented.  The CTMC data are all close 
             to this curve except at lower energies.  The hidden curve crossing data for Li+3 deviate
             from this curve.  Molecular orbital calculations by Errea et al. (1996) for B+5 are in
             good agreement with the corresponding CTMC data.  For He+2, the recommendation of Janev
             and Smith is based on the calculations of Harel and Jouin (1990) and it is completely
             different from the CTMC results for He+2, especially at the lower energies.  A reason
             for this huge difference is hard to see.  It may be the extremely strong resonant 
             nature of the electron capture at low collision energies.  Resonant transfer from H(n=2)
             in collsions with He+2 would necessarily mean that the electron ends up exactly between
             the n=3 and n=4 levels of He+1.  Therefore electron capture may be blocked. To what extent
             this is well described by the CTMC method is still a point of discussion.  For higher
             charged receiver ions, levels are resonantly present.  Except for He+2 at low energies, 
             we recommend use of the present CTMC data. 

             The data was assembled as ADAS data files of type adf01 at JET Joint Undertaking in the
             period 2-3 June 1997.    

  Authors:  F. W. Bliek*, R. Hoekstra*, R. E. Olson#
                  * KVI, Groningen, Netherlands
                  # University of Missouri, Rolla, USA. 

  Date:  9 June 1997.

  Updates: 

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Dependents

• ADF12 qef97#h_en2_kvi#he2.dat

Contributors

• Kernfysisch Versneller Instituut