NUCLEAR SHELL-MODEL AND INTERACTING BOSON-FERMION APPROXIMATION

The Interacting Boson-Fermion Model (IBFM) hamiltonian is derived star ting from the shell-model interaction, by a straightforward extension of the Otsuka, Arima and Iachello mapping procedure to odd-mass system s. Employing a single j-shell model and identical many nucleon systems , systematic studies of spectra giving the comparison in the shell-mod el, SD pair truncated model and IBFM are carried out: (i) for various proportions of monopole pairing and Q.Q interactions which simulate vi brational-rotational transition; (ii) for a particular combination of these interactions together with the quadrupole pairing interaction, w hich conserves seniority. (C) 1998 Elsevier Science B.V.