Benchmark calculations for simultaneous ionization--excitation of
helium

A.S. Kheifets$^\star$, I. Bray$^\sharp$ and  K.~Bartschat$^\dagger$

$^\star$ Research School of Physical Sciences and
Engineering, Australian National University, Canberra A.C.T. 0200,
Australia.

$^\sharp$Electronic Structure of Materials Centre, Flinders University
of South Australia, GPO Box 2100, Adelaide S.A. 5001, Australia

$^\dagger$Department of Physics and Astronomy, Drake University, Des
Moines, IA 50311, U.S.A.

Benchmark calculations are presented for the electron impact
ionization of He leaving the ion in the $n$=2 excited state. The
projectile-target interaction is described in the 1st Born
approximation whereas the interaction of the ejected and the remaining
target electron is treated non-perturbatively within the
close-coupling formalism, either in coordinate or momentum space. Good
agreement is found between these two methods, thereby creating a basis
for further improvement.