- th / 9 90 20 17 v 1 6 F eb 1 99 9 1 Study of effective interaction from single particle transfer reactions on f - p shell nuclei

The conventional search for an effective two-body interaction to be used in shellmodel studies involves numerically intensive mixed configuration calculations. It is, however, now known that meaningful averages of effective interaction matrix elements can be obtained through an alternative simpler method with the help of energy-weighted sum rules 1), 2), 3), 4), 5), 6). Monopole energy weighted sum rules have been used to derive explicit algebraic equations relating effective interaction matrix elements to isospin centroids of residual nuclear states obtained via single nucleon stripping and pick-up reactions performed on general multishell target states 4), 5). With the help of these, we have previously calculated the 1d5/2, 2s 2 1/2, 1d 2 3/2 and 1f 2 7/2 matrix elements of average effective interaction, working in each case within a limited vector space comprising of just one active orbit outside the postulated inert core 5), 6). The present work reports the application of these sum rules to stripping and pick-up reactions on target states belonging to f-p shell nuclei with shell occupancy no longer restricted only to single active orbit but also extended to two active orbits. The target states included in the current study have either 1f7/2 orbit or both 1f7/2 and 2p3/2 active orbits outside the inert core, 40Ca. We also study the target states having either 2p3/2 orbit or both 2p3/2 and 1f5/2 active orbits outside the inert core, 56Ni. The targets being investigated with 40Ca as inert core are 42,44,46,48Ca, 45Sc, 46,48,50Ti, 51V, 50,52,53,54Cr, 55Mn and 54,56,58Fe nuclei while those investigated with 56Ni as inert core include 58,60,61,62,64Ni, 63,65Cu, 64,66Zn, 69Ga and 70Ge isotopes.