Regular Article - Experimental Physics
Low lying particle-hole states in Pb and Pb and the shell model
, Gustav-Kirchhoff-Str. 7/1, 69120, Heidelberg, Germany
Accepted: 23 May 2021
Published online: 30 June 2021
The nucleus differs from the doubly magic nucleus by two missing neutrons. In most states at MeV are described by one-particle one-hole configurations. The lowest configurations with a g particle and dominant p, f, p holes and admixtures from f and a few more configurations build an ensemble of two dozen states at 3.2 MeV. They are described by rather complete orthonormal transformation matrices of two dozen states with spins from 2 to 8 to configurations. In a similar ensemble of states is deduced from the analysis of angular distributions measured in 1969 for the reaction via the g IAR in . An equivalent experiment was performed in 1968 at the Max–Planck–Institut für Kernphysik at Heidelberg (Germany). New spins are determined for 32 states and 22 levels in . The comparison to corresponding states in studied especially in 1982 yields both remarkable similarities and clear differences. Sizeable gp strength found in 4 and 5 states is interpreted as admixtures of and components to the ground state of with dominant character. The description of nuclear states by shell model particle-hole configurations in the lead region needs the inclusion of collective excitations at already very low excitation energies. For the two isotopes and a rather good agreement of excitation energies and configuration mixing is observed for states at 3.7 MeV.
© The Author(s) 2021
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