Charge-changing transitions in an extended Lipkin-type model
S. Stoica1 - I. Mihut1 - J. Suhonen2
1 Department of Theoretical Physics, Institute of Physics and Nuclear
Engineering, P.O. Box MG-6, 76900-Bucharest, Romania
2 Department of Physics, University of Jyväskylä, P.O. Box 35, FIN-40351, Jyväskylä, Finland
Received: 4 May 1998 Communicated by F. Lenz
Charge-changing transitions are considered in an extended Lipkin-Meshkov-Glick (LMG) model taking into account explicitly the proton and neutron degrees of freedom. The proton and neutron Hamiltonians are taken to be of the LMG form and, in addition, a residual proton-neutron interaction is included. Model charge-changing operators and their action on eigenfunctions of the model Hamiltonian are defined. Transition amplitudes of these operators are calculated using exact eigenfunctions and then the RPA approximation. The best agreement between the two kinds of calculation is obtained when the correlated RPA ground state, instead of the uncorrelated HF ground state, is employed and when the proton-neutron residual interaction, besides the proton-proton and neutron-neutron residual interactions, is taken into account in the model Hamiltonian.
21.60.Fw Models based on group theory - 21.60.Jz Hartree-Fock and random-phase approximations - 13.75.Cs Nucleon-nucleon interactions