INVESTIGADORES
MITNIK Dario Marcelo
artículos
Título:
The effects of coupling to the target continuum on the electron-impact excitation of Li+
Autor/es:
BALLANCE, C. P.; BADNELL, N. R.; GRIFFIN, D. C.; LOCH, S. D.; MITNIK, D. M.
Revista:
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
Editorial:
IOP
Referencias:
Lugar: Bristol, London; Año: 2003 vol. 36 p. 235 - 246
ISSN:
0953-4075
Resumen:
We have investigated the effects of coupling to the continuum and high
bound states on the electron-impact excitation of He-like Li+
using the R matrix with pseudostates (RMPS) method. Previous studies on
this ion have focused on transitions from the ground state to the n = 2
terms. In this work, we have determined collision strengths between all
19 terms through n = 4. We present the results of two RMPS calculations
with different numbers of pseudostates in order to study the convergence
of the collision strengths with the size of the pseudostate expansion.
In addition, we compare the RMPS collision strengths with the results of
an R-matrix calculation without pseudostates in order to determine the
influence of the continuum coupling as a function of electron energy. As
one might expect, coupling to the target continuum has quite large
effects on the collision strengths for excitation to the n = 3 and 4
terms at energies above the ionization limit. However, we find that
these effects are also significant for excitation to the n = 2 terms and
that they persist down to energies just above the excitation thresholds.
The experience gained from this work will allow us to pursue similar
studies in more complex target systems. Furthermore, the results of our
largest RMPS calculation provide the most complete and accurate set of
excitation data for this ion, which is of significant importance to
research in controlled nuclear fusion.