Neutron blocking in elastic α-scattering on Oxygen isotopes

doi:10.1016/0375-9474(82)90546-2

Nuclear Physics A

Volume 373, Issue 3, 18 January 1982, Pages 493-501

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Abstract

Elastic α-¹⁸O scattering has been studied microscopically within the framework of the generator coordinate method. The bound states of the α-¹⁸O system agree very well with the ²²Ne ground state band. The scattering phase shifts as well as the bound states show a strong parity splitting. A comparison with the α-¹⁶O system gives no evidence for a reduction of parity splitting due to the blocking of the ¹⁸O excess neutrons as suggested by Sünkel and Wildermuth.

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Microscopic study of α-cluster states in 22Ne
2003, Nuclear Physics A
α-cluster states of $^{22} Ne$ are investigated with an $α+^{18} O$ two-cluster model, using the generator coordinate method. The $^{18} O$ internal wave functions are defined in the shell model involving the s, p and sd shells. As a consequence, the model allows the description of many $α+^{18} O$ channels. Our results suggest the existence of a positive-parity molecular band. Furthermore they confirm the existence of negative-parity doublets located above the $α+^{18} O$ threshold. Electromagnetic transition probabilities and reduced widths associated with these states are given. A similar study is performed in the $^{22} Mg$ mirror nucleus.
Microscopic α-nucleus potentials
1983, Nuclear Physics, Section A
A formal relation connecting microscopic matrix elements of the generator coordinate method with effective nucleus-nucleus potentials of a Schrödinger-type equation of relative motion has been used to derive effective local energy-independent angular-momentum-dependent α-nucleus potentials from microscopically calculated angular-momentum-projected energy surfaces. Application to the target nuclei ^{40, 42, 44, 48} Ca ^{16, 18}O, ¹⁴C and ²⁸Si gives α-nucleus potentials which depend smoothly on angular momentum and on the mass of the target nucleus. At small separations, the α-nucleus interaction is dominated by the requirement of orthogonality of the relative motion wave function to Pauli-forbidden states of relative motion. In all cases studied the effective local potentials reproduce the elastic scattering phase shifts of a full microscopic GCM calculation remarkably well.
Resonant structures in elastic cross sections for channels with strong angular momentum mismatch
1983, Nuclear Physics, Section A
The influence of a strongly angular momentum mismatched inelastic 0⁺ channel on the resonant structure in the elastic channel has been studied microscopically for the α-¹⁸O system within the framework of the coupled-channel generator coordinate method. The structures in the elastic cross section have been identified as resonances in either the elastic or inelastic channel. The coupling between the two channels takes mainly place in the internal nuclear region where antisymmetrization is indispensable. The Pauli principle causes especially an l-dependent coupling. The validity of the present results is qualitatively discussed for the ¹²C-¹²C, ¹⁶O-¹⁶O and ²⁸Si-²⁸Si systems. For the ¹⁶O-¹⁶O system, a strong influence of the Pauli principle on the diagonal and coupling potentials is predicted.
Microscopic study of elastic 28Si28Si scattering and intermediate structure resonances in 56Ni
1982, Physics Letters B
Explanation of the backangle anomaly and the isotope effect within a microscopic study of elastic α-scattering on the even Ca isotopes
1982, Nuclear Physics, Section A
Elastic α-scattering on the isotopes ^40,42,44,48Ca has been studied microscopically within the framework of the generator coordinate method. For energies above the Coulomb barrier the backangle enhancement of the cross section in elastic α-⁴⁰Ca scattering is explained by several overlapping barrier resonances, while for energies below the barrier the backangle rise is caused by individual long-living resonances which — in agreement with recent experimental data — confirm the concept of an “α-⁴⁰Ca quasimolecule”. The isotope effect showing up in a different behaviour of the cross section at backangles is due to a different absorptive strength of the isotopes. “Neutron blocking” has been ruled out as a possible explanation of the isotope effect.
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Nuclear Physics A

Abstract

References (23)

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Phys. Rev.

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diploma thesis

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Cited by (14)

Microscopic study of α-cluster states in <sup>22</sup>Ne

Microscopic α-nucleus potentials

Resonant structures in elastic cross sections for channels with strong angular momentum mismatch

Microscopic study of elastic <sup>28</sup>Si<sup>28</sup>Si scattering and intermediate structure resonances in <sup>56</sup>Ni

Explanation of the backangle anomaly and the isotope effect within a microscopic study of elastic α-scattering on the even Ca isotopes

Time-Dependent Description of Incomplete Fusion of Nuclei and Cluster and Nucleon-Transfer Reactions