Microscopic analysis of quadrupole collective motion in Cr-Fe nuclei. I. Renormalization of collective states and interacting boson model parameters

We present a new method by which wave functions with simple structure are renormalized so as to contain more complicated structure. This method, called Hn-cooling method, is applied to the study of the quadrupole collective motion of 56Fe, 54Cr, 58Fe, and 56Cr. The shell-model wave functions of lowest-lying states of these nuclei are well treated by this method. By using the wave functions obtained via the Hn-cooling method, interacting boson model-2 parameters are derived from a realistic shell-model Hamiltonian and transition operators. The Majorana interaction becomes sizably repulsive, primarily as an effect of the renormalization. The bosonic E2 effective charges are enhanced due to the renormalization, while a quenching occurs in the M1 and M3 parameters for proton bosons. It is shown that the χ parameters take similar values in the Hamiltonian and in the E2 operator. copyright 1997 The American Physical Society