Delta excitations in compressed finite nuclei. II. Nucleon-nucleon interaction dependence.

Abstract

Spherical Hartree-Fock calculations at equilibrium and under radial compression are presented for $^{40}\mathrm{Ca}$ and $^{90}\mathrm{Zr}$ in a model space of seven major oscillator shells. We employ an effective baryon-baryon interaction which includes the \ensuremath{\Delta}(1236) resonance explicitly. The nucleon-nucleon (N-N) interactions are based on the Nijmegen and Reid soft core potentials. The results indicate a significant dependence on the choice of the N-N interaction at large nuclear compression. We found mixing between nucleons and \ensuremath{\Delta}'s even at equilibrium in $^{90}\mathrm{Zr}$ with either choice of potentials, but not in $^{40}\mathrm{Ca}$. Substantial amounts of the excitation energy induced by compression goes to the creation of \ensuremath{\Delta} excitations. \textcopyright{} 1996 The American Physical Society.