ISSN:0094-243X    

DOI:10.1063/1.42558

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Recent progress on the study of neutron‐rich unstable nuclei is reviewed. Density distributions of halo nuclei Be and Li are discussed in relation with the medium‐ and high‐energy reaction cross sections with various targets. It is pointed out that the enhancement of the cross sections of halo nuceli is described well by the Hartree‐Fock densities calculated under the constraint for the separation energy. There is no indication of the large deformation in the experimental data of the reaction cross sections, the projectile fragmentations and the Q‐moments of halo nuclei. Multipole resonances in the nucleus10He are studied by using self‐consistent Hartree‐Fock+RPA response function theory. A bunch of resonances with multipolesJ&pgr;=0+,1−and 2+is found near the thresholdEx∼l MeV having significant portions of the sum rule values with narrow widths. The long‐range feature of the Hartree‐Fock potential reflecting the tail of the loosely‐bound neutrons is responsible for the bunching of the resonances.

ISSN:0094-243X    

DOI:10.1063/1.42559

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.42560

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.42561

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

In the present contribution, we concentrate on the specific effects the proton‐neutron force implies when studying low‐energy nuclear structure phenomena. We discuss various cases where a proton‐neutron quadrupole component can lead to systematic changes in the nuclear structure:N&pgr;Nvscaling in open‐shell nuclei and low‐lying 0+intruder excitations near closed shells. We moreover describe the influence of the proton‐neutron force in a dynamic way on the nuclear radius in nuclei near closed shells using a shell‐model and a collective model (vibrations) approach.

ISSN:0094-243X    

DOI:10.1063/1.42562

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The critical role of the residual valence p‐n interaction in the development and evolution of collectively, and the onset of shape/phase transition, is discussed from the standpoint of phenomenological approaches, the empirical extraction of individual p‐n interaction strengths, and simple model calculations of them.

ISSN:0094-243X    

DOI:10.1063/1.42563

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Extension of our knowledge of N=Z nuclei up toMo4284are reviewed. Only &ggr;-ray singles data are available forGe64toMo84, so more definitive tests of theoretical predictions of shape coexistence and deformation changes among them are not possible with present data. The limitations of current facilities to probe in the necessary detail the N=Z line and to extend it further are discussed. A new generation recoil mass spectrometer has been designed for HHIRF to overcome present limitations. The key new feature is a momentum achromat in front of a traditional RMS. A proposed radioactive beam facility for HHIRF, along with the new RMS is shown to open up studies of the N=Z line toSn50100and beyond.

ISSN:0094-243X    

DOI:10.1063/1.42596

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

An overview is given over relativistic mean field theory for finite nuclei. Applications for the description of ground states of spherical and deformed nuclei are discussed. High‐spin states and superdeformed bands are investigated within the framework of a relativistic extension of the cranking theory. A field theoretical theory for pairing correlations is presented, and it is shown that the parameter sets used so far in the literature for relativistic mean field theory are not able to describe the superfluid behavior of nuceli in a reliable way.

ISSN:0094-243X    

DOI:10.1063/1.42564

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The features of the EUROGAM multidetector array, composed of 45 Ge with their associated anti‐Compton shield are presented. The properties of the detectors and an upgrade of the geometry are described. The data acquisition system incorporates integrated electronic designed with the new VXI standard; the whole system is distributed on a network and takes benefit of UNIX based workstations and the real time facilities of VxWorks.

ISSN:0094-243X    

DOI:10.1063/1.42566

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

A systematic occurrence of the super‐ and hyper‐deformed nuclear configurations is illustrated for 58≤Z≤92 nuclei. The cases selected correspond to the most stable among those exotic configurations. Here we arbitrarily qualify the configurations as ‘‘reasonably stable’’ if the corresponding minima on the total energy surfaces are surrounded by the potential barriers of at least 1000 keV. (Most of the interesting cases correspond to much higher barriers). The strongest effects predicted correspond to ⋅Z∼(76–84) nuclei where the hyper‐deformation at both low and high spins seems to be a ‘‘usual situation’’.

ISSN:0094-243X    

DOI:10.1063/1.42567

出版商:AIP    

年代:1992

数据来源: AIP