https://doi.org/10.1007/s100530050296
Note on electron impact excitation for transition
of Be-like
isoelectronic sequence
Physics Department, National University of Singapore, Singapore 119260
Received:
25
February
1998
Revised:
18
June
1998
Published online: 15 May 1999
Relativistic distorted-wave method was used to calculate
the electron impact excitation
collision strengths for transitions 
-
of Be-like
isoelectronic ions.
The target states
were described, respectively, by
10-level, 46-level and 133-level MCDF configuration-expansion. The relativistic
continuum orbitals were calculated in the potential field of frozen target-ion
charge distribution with semi-classical exchange potential.
The influence of the target states on
this collision process along
the isoelectronic sequence was investigated in the above three MCDF
configuration-expansion modes. It was found that the configurations in the n=3 and
the n=4 complexes have great influence on both the high and the low Z ions
but the influence is relatively small for intermediate Z ions. The
latter phenomenon was attributed to competition between opposing
correlation and relativistic effects on the collision strengths.
PACS: 34.50.Fa – Electronic excitation and ionization of atoms (including beam-foil excitation and ionization) / 34.80.Kw – Electron-ion scattering; excitation and ionization
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
