Quadrupole Interaction and High-Spin States in the Lead Region

Self Cite

High-spin levels in 2~ populated in the 2~ were studied using c~-particles in the energy region 41-51 MeV. The energies of levels above the 6 + level have an uncertainty of about 10 keV due to the fact that the 8 +--.6 + transition has not been observed so far, but this transition has previously been established to be converted neither in the K-shell nor in the L-shells. It was found that the yrast cascade of y-rays from a 19 + level at 5896+ekeV feeds levels of lower spin which all can be explained as originating from two proton-two neutron hole configurations. In the higher part of the cascade it is mainly the neutron holes which change their configuration, while the lower part of the cascade is dominated by changes in the proton configuration. The yrast levels in the angular momentum region J--8-19 vary practically linearly with energy in the region 1.5-6 MeV. No isomeric traps were found above the 11-level at 2699 + e keV.

Section: Discussionsupporting

confidence: 68%

On the yrast two proton-two neutron hole states in208Po

Bergström¹,

Blomqvist²,

Herrlander³

et al. 1978

Self Cite

“…States of this type were, in fact, predicted long ago [18]. For two protons outside a lead core an additional interaction has been observed, the so-called corepolarization [19], a long-range core-mediated quadrupole interaction. The coupling between particles i and j is expressed as Z ~ Pz(cosi~), where Z is the i<j core-dependent strength parameter.…”

Section: Theoretical Considerationsmentioning

confidence: 97%

“…The coupling between particles i and j is expressed as Z ~ Pz(cosi~), where Z is the i<j core-dependent strength parameter. From known states built on 2~176176 an empirical relation for the coupling strength as a function of mass number A is obtained [19]. A linear fit to these values yields z(A) = -59.557 + 0.281A (MeV).…”

Section: Theoretical Considerationsmentioning

confidence: 99%

In-beam studies of203, 205Bi and shell-model features of odd-a bismuth isotopes

Lönnroth

1982

States in 2~176are populated using the reaction 2~176The ~i13/2 single-proton states and all the members of the v(2~-)| rc h9/2 quintuplet are identified in both nuclei. The half-lives of the isomeric J~=21/2 § states in both isotopes are measured and found to be 90_+7ns and 100_6ns, and from these values suggestions for the half-lives of the previously reported J~= 25/2 -~ isomers are made. The structures of the multiplets of the form v(Pb)| are calculated in the framework of the shell model and it is shown that the main features can be derived from the re-v-a effective interaction. The wave functions of the 4~ and 4~ states in /~176 are deduced indirectly from the calculation in 2o3.2OSBi"

“…Since for high spin states, isomers often corresponds to the aligned angular momenta of the valence nucleons [2], the possibility exists that the isomer corresponds to J=16 + of the Irch}/2 2 vg9/2) configuration. However no 7-ray with an energy equal to or greater than 100keV and having the required intensity was observed in the present work.…”

Section: Discussionmentioning

confidence: 99%

Spectroscopy of excited states in216Ra

Chevallier¹,

Chevallier²,

Haas³

et al. 1982

A gamma spectroscopic investigation of 216Ra was performed by means of the reactions 2~ 3n) and 2~ 4n). Yield functions, angular distributions, 7-y coincidences, time centroid shifts and pulsed beam isomeric decay rates were measured. The yrast level structure is firmly established up to spin 14 and information on the ytransitions from higher lying levels is also obtained. The configurations of the low-lying levels are discussed.