Effective Interaction and Effective Charge for Valence Nucleons in Collective Vibration and Core Polarization

Abstract

It is necessary to investigate the reality or origin of the “pairing plus Q-Q force” in order to study the mechanism of the collective motions in medium and heavy nuclei. The effective interaction and the effective charge renormalized by the core polarization are calculated from the reaction matrix derived from the nuclear force. The adiabatic approximations are made between the collective oscillation and two-particle ladder scattering and also between the oscillation of the core and that of the valence nucleons. Calculations are made exactly without using the perturbation expansion. The core polarization enhances the particle-hole interactions for J = 2, 4, 6 remarkably and almost unchanges those for J = 1, 3, 5. The resulting renormalized effective interaction has properties somewhat advantageous to the collective enhancement. The J = 2 particle-hole interaction becomes, however, much larger than the usual Q-Q force, while the J = 0 particle-particle interaction is not much larger than the usual pairing interaction. The calculated effective charge is rather too small. Thus the results do not agree with the physical picture with the usual “pairing plus Q-Q force”.