摘要:

We present the M1 excitation scheme in even‐even deformed nuclei from the sum‐rule viewpoint based on the Nilsson+BCS approach. The sum‐rule states are introduced for the Scissors, spin and spin‐flip modes. The functional form of the B(M1) sum rule of the Scissors mode is obtained, and its actual value is shown to be 4∼6(&mgr;N2). The spin excitation B(M1) is 10∼15(&mgr;N2) including the spin‐flip transitions. The total B(M1) is 15∼20(&mgr;N2). The effect of the SD and SDG pair truncation is studied to test IBM‐2 for M1 excitations. The SDG truncation reproduces very well the calculation without truncation. The SD truncation reproduces the orbital excitation, whereas yields some deviations for the spin excitation.

ISSN:0094-243X    

DOI:10.1063/1.41168

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

It is becoming clearer with time that non‐locality of the nucleon‐nucleon interaction can play a significant role in nuclear properties. In this talk we review evidence for such nonlocality. Then, using a Gaussian interaction, we discuss the effect of non‐locality on two body matrix elements in the nuclear shell model. Finally, we mention some applications. For example, non‐locality leads to faster convergence of off‐diagonal matrix elements.

ISSN:0094-243X    

DOI:10.1063/1.41169

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Mixed‐symmetric 2+state of56Fe is investigated by shell model in a large configuration space in thepf‐shell. We can reproduce experimental energy levels by using Kuo‐Brown interaction. The (e,e’) form factors are also reproduced quite well by including the core polarization effect. By analyzing these reliable shell model wavefunctions, we conclude that the 22+and the 24+states share the main part of mixed‐symmetry state.

ISSN:0094-243X    

DOI:10.1063/1.41149

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The IBM‐2+ Configuration Mixing method has been expanded, in order to consider several multiparticle‐multihole (np‐mh) configurations simultaneously. The various np‐mh configurations obtained by exciting pairs of protons and/or neutrons across major shell gaps are treated in a consistent manner, along with the normal configurations for a nucleus. As a test, the method is applied to the nucleus192Hg. Previously determined parameters are utilized for the normal (0p‐2h) proton configuration and the expected shape‐coexisting (2p‐4h) proton configuration. Three other excited np‐mh configurations are included, with a consistent set of Hamiltonian parameters.

ISSN:0094-243X    

DOI:10.1063/1.41150

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Excitation modes of non‐axial quadrupole shapes are investigated in the framework of interacting boson models. Both &ggr;‐unstable and &ggr;‐rigid nuclear shapes are considered for systems with one type of boson as well as with proton‐neutron bosons.

ISSN:0094-243X    

DOI:10.1063/1.41151

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Experimental B(E2; 01+→21+) values for 54 even‐even nuclei in the range A=90–200 were used to deduce effective charges of proton, neutron bosons. The results indicate that for deformed nuclei, the ratio en/epis in general agreement with the schematic Bohr and Mottelson prediction. For vibrational nuclei in the A=100 and A=140 regions a very significant enhancement of this ratio is found.

ISSN:0094-243X    

DOI:10.1063/1.41152

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Describing the coexistence of normal and intruder states within the framework of the neutron‐proton Interacting Boson Model, some inconsistency in the choice of the neutron‐proton quadrupole force strength is pointed out. It is shown that this can be removed by rigorously calculating the unperturbed energy of the intruding configuration. This is illustrated by a calculation of the excited levels in114Cd.

ISSN:0094-243X    

DOI:10.1063/1.41159

出版商:AIP    

年代:1991

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.41160

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The multipole structure of the effective proton‐neutron interaction was analyzed in the odd‐odd In nuclei by fitting a dipole plus quadrupole interaction to the splitting of 11 multiplets of110−116In. It was found that the quadrupole‐quadrupole interaction is about twice as strong as in the doubly magic region. The additional quadrupole‐quadrupole interaction strength found is in agreement with the predictions of the particle‐vibration theory.1

ISSN:0094-243X    

DOI:10.1063/1.41161

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The experimental data on two quasi‐particle (2qp) rotational bands of even‐even rare‐earth nuclei reveal significant odd‐even staggering in both K+=(&OHgr;1+&OHgr;2) and K=‖&OHgr;1−&OHgr;2‖ bands. An empirical rule is proposed for the phase of staggering and is checked with the experimental data. More complexities are exhibited by these rotational bands as compared to odd‐odd nuclei which are evidenced in the form of anomalous behavior seen in the cases where data are known up to higher spins.

ISSN:0094-243X    

DOI:10.1063/1.41162

出版商:AIP    

年代:1991

数据来源: AIP