Gertrude Scharff-Goldhaber

“Forking” of ground state bands in 102Pd and 100Pd

Abstract A new phenomenon is observed in the level schemes of 102Pd and 100Pd, populated by heavy ion induced reactions: the ground state bands of these nuclei reach J = 14, but “fork” into two branches, at the 8+ state in 102Pd and at the 6+ state in 100Pd. A ground state band in the near-magic nucleus 98Pd, whose level energies were previously unknown, was populated to J = 8.

Possible quasi-molecular rotational bands in sd-shell nuclei☆

Abstract Analysis of elastic 12 C + 12 C and 16 O + 16 O scattering suggests the presence of families of shape resonances, which are found to lie on rotational bands. They are compared with the corresponding ground-state bands, and alternative means or exciting them are suggested.

Activities observed in iridium after neutron bombardment. Remarks on a paper by H. H. Hennies and A. Flammersfeld

Recently Hennies and Flanunersfeld (Naturwissenschaften, 47: 11(1960)) reported ths observation of a new 47-sec activity produced by irradiating Ir powder with slowed-down neutrons. The activity was tentatively assigned to Ir/ sup 194//sup m/. Beta activities, previously ascribed to Ir/sup 192//sup m/, were reassigned to Ir/sup 194//sup m/. A repetition of the experiment on the bombardment of Ir/sup 193/ with slow neutrons (Phys. Rev. Lettens, 3: 4S(1959)) confirmed the previous conclusions and ruled out a 47-sec period in Ir/sup 192/ or Ir/sup 19 / 4>s. It was suggested that the Hennies and Flammersfeld results may be partly ascribed to a Rh impurity and partly to the effect of fast neutrons. (J.S.R.)

Level schemes ofPd102andPd100

High-spin states have been populated in /sup 102/Pd by /sup 92/Zr(/sup 13/C,3n..gamma..)/sup 102/Pd with E/sub lab/=56 MeV and in /sup 100/Pd by /sup 91/Zr(/sup 12/C,3n..gamma..)/sup 100/Pd with E/sub lab/=63 MeV. We find in each nuclide a ground-state band (..delta..J=2) of positive parity extending to J/sup ..pi../=14/sup +/, as well as two negative parity bands (..delta..J=2), one of odd spin and one of even spin. For /sup 100/Pd, the present level scheme represents the first definitive study of excited states in this nuclide. For /sup 102/Pd the present data include the first measurement of the ..gamma..-ray linear polarizations. The level energies are compared to the variable moment of inertia model, the interacting boson approximation model, and to the results of a quasiparticle calculation.

Present status of the VMI and related models

Abstract This article traces the evolution of the Variable Moment of Inertia model in its relation to the shell model, the Bohr-Mottelson model and the Interacting Boson Model. The discovery of a new type of spectrum, that of “pseudomagic” nuclei (isobars of doubly magic nuclei) is reported, and an explanation for their dynamics is suggested. The type of rotational motion underlying the ground state band of an e-e nucleus is shown to depend on whether the minimum number of valence nucleon pairs of one kind (neutrons or protons) is⩽ 2 or > 2. In the former case the “alphadumbbell model” holds; in the latter the “two-fluid model.”

Level schemes of /sup 102/Pd and /sup 100/Pd

High-spin states have been populated in /sup 102/Pd by /sup 92/Zr(/sup 13/C,3n..gamma..)/sup 102/Pd with E/sub lab/=56 MeV and in /sup 100/Pd by /sup 91/Zr(/sup 12/C,3n..gamma..)/sup 100/Pd with E/sub lab/=63 MeV. We find in each nuclide a ground-state band (..delta..J=2) of positive parity extending to J/sup ..pi../=14/sup +/, as well as two negative parity bands (..delta..J=2), one of odd spin and one of even spin. For /sup 100/Pd, the present level scheme represents the first definitive study of excited states in this nuclide. For /sup 102/Pd the present data include the first measurement of the ..gamma..-ray linear polarizations. The level energies are compared to the variable moment of inertia model, the interacting boson approximation model, and to the results of a quasiparticle calculation.

Level schemes of Pd-102 and Pd-100

High-spin states have been populated in /sup 102/Pd by /sup 92/Zr(/sup 13/C,3n..gamma..)/sup 102/Pd with E/sub lab/=56 MeV and in /sup 100/Pd by /sup 91/Zr(/sup 12/C,3n..gamma..)/sup 100/Pd with E/sub lab/=63 MeV. We find in each nuclide a ground-state band (..delta..J=2) of positive parity extending to J/sup ..pi../=14/sup +/, as well as two negative parity bands (..delta..J=2), one of odd spin and one of even spin. For /sup 100/Pd, the present level scheme represents the first definitive study of excited states in this nuclide. For /sup 102/Pd the present data include the first measurement of the ..gamma..-ray linear polarizations. The level energies are compared to the variable moment of inertia model, the interacting boson approximation model, and to the results of a quasiparticle calculation.