Ka-Hae Kim

Three-dimensional TDHF calculations for reactions of unstable nuclei

The fusion is studied for reactions between a stable and an unstable nuclei with neutron skin. The reactions and are taken as examples, and the three-dimensional time-dependent Hartree - Fock method with the full Skyrme interaction is used. It is shown that, in such reactions, the nucleon transfer is enhanced enormously for both protons and neutrons. As a whole, it is seen that the neutron skin does not enhance the fusion cross section in the calculations made so far.

IBM-2 calculations of even-even Pd nuclei

Abstract Excitation energies, electromagnetic transition strengths and static moments in even-even Pd nuclei have been described systematically by using the proton-neutron interacting boson model (IBM-2). Parameters are fitted so as to be consistent with microscopic calculations. Mixed symmetry 2 + states have been identified using the M1 transition strength. The F -spin impurity of the first 2 + state is investigated by means of g -factors and M1 transitions. The calculations have been extended to neutron-rich Pd isotopes with A > 116 for which excited states are still not known.

A relation between E2 matrix elements connecting collective states of deformed nuclei

Abstract A relation is presented stating that a sum of certain products of E2 matrix elements connecting the 0+ and 2+ levels in the ground, β-, and γ-bands in the limit of strong quadrupole deformation vanishes. As a consequence β → g E2 matrix elements are much smaller than β → γ matrix elements, contrary to the naive expectation based on the vibrational picture of independent β and γ excitations. This relation is supported by experimental data on deformed nuclei, and suggests a re-examination of the traditional understanding of these basic collective modes and their inter-relationships.

Transfer and fusion reactions of unstable nuclei

Abstract The transfer and fusion reactions are studied for reactions between a stable and an unstable nucleus with neutron skin, taking as examples the reactions 16,28O+40Ca. The two-dimensional time-dependent Hartree-Fock method is used. It is shown that, in such reactions, the nucleon transfer is enhanced enormously for both protons and neutrons. The neutron skin does not enhance the fusion cross section contrary to the usual expectation.

SUPERSYMMETRIC OPERATOR FOR THE U(6/4) DYNAMICAL SYMMETRY

Abstract An explicit form of the supersymmetric operator is constructed algebraically for the case of the U(6/4) dynamical symmetry. It converts the eigenstates of the even nucleus into corresponding eigenstates of the odd SUSY partner nucleus. It gives an explicit form of the wave function of the states of the odd nucleus in terms of the supersymmetric operator. A comparison with the particle–core model is given.

Shape transitions in proton-neutron systems☆

Abstract We explore the possibility of shape transitions in proton-neutron systems driven by deformation differences between proton and neutron fluids. Within the framework of the proton-neutron interacting boson model, we show that such dynamic shape transitions cannot occur in well deformed nuclei but are a possibility in transitional nuclei. Likely candidates in the Os-Pt isotopes are discussed and predictions of the model are compared with the existing data.