  Large-space no-core shell model calculations have been performed for A=3-6
nuclei, using a starting-energy-independent two-body effective interaction
derived by application of the Lee-Suzuki similarity transformation. This
transformation can be performed by direct calculation or by different iteration
procedures, which are described. A possible way of reducing the auxiliary
potential influence on the two-body effective interaction has also been
introduced. The many-body effects have been partially taken into account by
employing the recently introduced multi-valued effective interaction approach.
Dependence of the He5 energy levels on the harmonic-oscillator frequency as
well as on the size of the model space has been studied. The Reid 93
nucleon-nucleon potential has been used in the study, but results have also
been obtained using the Nijmegen II potential for comparison.
