Abstract
The one-boson-exchange potentials in the momentum representation of Holinde and Machleidt (see Nucl. Phys. A, vol.256, p.497, 1976) are used in a shell-model calculation of the spectra of mass-18 nuclei in order to gain an insight into the possibilities of convergence of the effective interaction expansion for these nucleon-nucleon interactions. The spectra are calculated in first order, and also in first order including the core polarisation term, which is the most important second-order correction. Comparison is made with the Reid soft-core potential results.