Core-particle coupling and polarization effects

Abstract

The unpaired particle in an odd-mass transitional nucleus exerts forces on the rest of the system leading to an effective shape which is in general dependent on the j-orbital occupied by the extra particle. To account for this polarization effect we propose to modify the collective matrix elements by a phenomenological polarization factor. This enables us to describe also such band structures by the core-particle coupling model for which the common coupling rules seem to fail. Selecting a typical case the model is applied to 123I in order to demonstrate the important role of the polarization. The calculation reproduces fairly well all band structures including their M 1 and E2 decay properties.

Kerman-Klein-Dönau-Frauendorf model for odd-odd nuclei: Formal theory

“…From a practical point of view, it suffices to diagonalize the Hamiltonian H e using the complete set of states (physical and spurious) generated by H o and selecting the largest half of the eigenvalues as the physical solutions. The diagonalizationof H e within the subspace of physical (positive energy) states of H o performed originally when solving the model [3] can lead to a bad approximation of physical solutions of H or even give some unphysical solutions, since matrix elements of H e between physical and unphysical solutions need not be small. It is of interest to contrast this procedure with the one used earlier in which the term H e was turned on adiabatically and the physical solutions followed by using a wave function overlap argument.…”

Deformation dependence of magnetic moments in the odd transitional nuclei117?125Te

“…The excitation spectra and electromagnetic properties of odd nuclei in the Z--50 region are well described within CPC calculations [13,20,21]. In these calculations the experimental findings of the underlying even cores with mass numbers A-1 and A+ 1 are included.…”

Influence of the pairing parameter rotation dependence on signature splitting in odd-A nuclei

“…In this model the odd nucleon is considered as a quasiparticle which represents either a particle coupled to the A--1 core or a hole coupled to the A + 1 core or a superposition of both. A general formalism of the core-quasiparticle coupling model with two different cores has been presented by D6nau and Frauendorf [3]. In the present paper we include into this model the spin dependence of the pairing parameter.…”

“…In (6) and (7 a, b) we have included the averaged pairing parameter Aj (defined by (10)) depending on the total angular momentum J instead of constant A. In the second step, the diagonalization of the collective Hamiltonian is performed in the basis of the deformed one-quasiparticle states [3]. In the approximation of the one-quasiparticle state basis the matrix elements of the collective Hamiltonian, H c~…”

“…In the present paper we include into this model the spin dependence of the pairing parameter. In the core-quasiparticle coupling model the total odd-A nucleus wave function spanned by the spherical basis has the form [3]:…”