Structure of 12Be: intruder d-wave strength at N=8.

Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom.
Physical Review Letters (Impact Factor: 7.73). 02/2006; 96(3):032502. DOI: 10.1103/PhysRevLett.96.032502
Source: PubMed

ABSTRACT The breaking of the N=8 shell-model magic number in the 12Be ground state has been determined to include significant occupancy of the intruder d-wave orbital. This is in marked contrast with all other N=8 isotones, both more and less exotic than 12Be. The occupancies of the [FORMULA: SEE TEXT]orbital and the [FORMULA: SEE TEXT], intruder orbital were deduced from a measurement of neutron removal from a high-energy 12Be beam leading to bound and unbound states in 11Be.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Inspired by the recent measurement of the B(E2;$0_{2}^{+} \to 2_{1}^+$) and B(E0;$0_{2}^{+} \to 0_{1}^+$) values in $^{12}$Be, we give an interpretation of available spectroscopic data on both $^{12}$Be and $^{11}$Be, using a simple model which contains the essential feature of these two nuclei; the presence of weakly-bound neutron(s) in deformed potentials. The agreement of the calculated results with observed data is surprisingly good, including well-known strong E1 transitions in both nuclei.
    Journal of Physics G Nuclear and Particle Physics 08/2007; · 5.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We analyze the 12Be spectrum with two microscopic methods. Microscopic cluster calculations are performed within the Generator Coordinate Method (GCM) framework. An extended two-cluster model which includes the He8(0+,2+)+α, and He6(0+,2+)+He6(0+,2+) channels is developed. It represents an extension of a previous work by Descouvemont and Baye where only the 0+ ground states of 8He and 6He were taken into account. The GCM calculations lead to a good description of the molecular band suggested by Freer et al. and by Saito et al. The 02+ isomeric state and the 22+ state are also well described by the GCM. New bands of positive and negative parities are proposed. This approach is complemented by No-Core Shell Model (NCSM) calculations, in order to clarify the structure of the ground state and the hypothesis of an associated rotational band. The GCM and NCSM calculations do not support the existence of a band built on the ground state.
    Nuclear Physics A 01/2010; 836(3):242-255. · 2.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigated molecular states and cluster gas-like states in light nuclei based on theoretical calculations with antisymmetrized molecular dynamics. The calculated results of 13B suggest that largely deformed states construct rotational bands, Kπ=3/2−Kπ=3/2− and Kπ=1/2+Kπ=1/2+, starting from 5 MeV and 8 MeV, respectively. The neutron structure of the Kπ=3/2−Kπ=3/2− is analogous to the intruder ground state of 12Be. In the predicted Kπ=1/2+Kπ=1/2+ band, we found largely deformed structure with a proton excited configuration. The band-head 1/2+1/2+ state is assigned to the 1/2+1/2+ (4.83 MeV), which was experimentally suggested to be the proton intruder state. Structure of 8He were also investigated. In the results, it was found that the ground state of 8He has both the j-j coupling feature (p3/2p3/2 closure) and the L-S coupling feature (4He+2n+2n+2n+2n). The results also suggest possible existence of the 02+ state with dineutron gas-like structure of 4He+2n+2n+2n+2n, which has an analogy to the 3α-cluster structure of the 12C(02+) state.
    Nuclear Physics A 06/2008; 805(s 1–4):392c–399c. · 2.50 Impact Factor

Full-text (2 Sources)

Available from
May 22, 2014