The single-particle potential V(r) = - V-0[1 + (r/R)(beta)](-1), which has
been proposed in the recent years for atomic metal clusters, is studied ana
lytically in the case beta = 2. By using perturbation-type techniques, appr
oximate analytic expressions are obtained for the energy eigenvalues and ot
her physically interesting quantities showing the variation of these quanti
ties with the number of valence electrons. The accuracy is tested for Al cl
usters and is usually very good. (C) 1999 Elsevier Science B.V. All rights
reserved.