New developments in the nuclear binary cluster-core in the heavy nuclear region

[摘要] ENGLISH ABSTRACT : The atomic nucleus is a complex many-body interacting system, which exhibitsa underlying correlated set of nucleon states. The cluster model is one ofthe most reliable models that predicts the strongly correlated subsystem ofnucleons close to the decay threshold of nuclei. The binary-cluster modeldescribes the structure and decay properties of super-heavy nuclei.The phenomenological CubicWoods-Saxon potential, developed by Buck, Merchantand Perez, has successfully predicted a number of experimental observablesassociated with clustering phenomenon. The recently developed microscopicdouble folded M3Y potential results in the inverted spectra for thepositive parity excited cluster states, but successfully predicts the decay halflifefor the α-Pb system. These shortcoming of the M3Y based microscopicbinary cluster model lead to the newly developed hybrid cluster-core potential,obtained by fitting the phenomenological Saxon-Woods Cubed and the M3Ydouble folding at the surface region where the two potentials coalesce.The project presents an overview on nuclear cluster models. The double foldingpotentials are constructed with the M3Y and the new complex effective Gaussianform factor (CEG) effective nucleon-nucleon interactions. Furthermorethe recently developed self-consistent relativistic mean-field cluster-core descriptionis presented with the relativistic Love-Franey amplitudes. The decayhalf-lives for α-Pb give satisfactory results for M3Y and CEG with the addition of a zero-range exchange potential. However, the CEG with a finite-range andthe relativistic mean field approach potentials for all cluster-core configurations α-Pb, C-Pb and O-Pb except Be-Pb, give decay half-lives that overestimatethe experimental values. The generated positive parity level structures areinverted for α -Pb when compared to other cluster configurations which arecompressed although positive. Finally we construct the hybrid cluster-corepotential from different microscopic potential models. We find that predictionsfor the positive parity level structure, the transition probability, nuclearcharge radii and deformation parameters are in good agreement with the correspondingexperimental data for most cluster-core configurations.

[发布机构] Stellenbosch University