Two-body correlations inN=8and 10 nuclei and effective neutron-neutron interactions in Tamm-Dancoff and two-particle random phase approximation models

Abstract

We apply a particle-particle RPA model to study the properties of the two-neutron valence wave function in nuclei 14 C, 12 Be, 11 Li and 14 Be. The RPA model takes account of twobody correlations in the cores so that it gives a better description of energies and amplitudes than models which assume a neutron closed shell (or subshell) core. With a Gogny neutronneutron effective interaction or with the equivalent density dependent delta force we are able to reproduce the two-neutron separation energies in these nuclei and in the corresponding cores, except for 9 Li. These calculations suggest the same 2s-1p 1/2 shells inversion in 12 Be-13 Be than in 11 Be.

Structure of Be13 studied in proton knockout from B14

“…In 13 Be, which is the subject of our study, a large weight of a 10 Be ⊗ (sd ) 3 configuration is expected in the ground-state wave function. 12 Be cannot reasonably be considered a closedshell nucleus, as discussed in many papers about 13 Be and 14 Be [20][21][22][23][24][25][26].…”

Structure ofBe12: Intruderd-Wave Strength atN=8

“…Whereas high-energy single-neutron removal (or ''knockout'') from 12 Be has provided direct evidence for configuration mixing involving the 1s 1=2 2 and 0p 1=2 2 valence neutron configurations in the ground-state [3], model predictions indicate that a substantial 0d 5=2 2 admixture (30%-50%) should also be present [10,[12][13][14][15]. In the experiment of Navin et al, 11 Be core fragments in either the J 1=2 ground state or the bound 320 keV 1=2 ÿ excited state were detected [3].…”

Be14(g.s.)and single-particle energies inBeFortune 2014Phys. Rev. C10010View full textAdd to dashboardCite

“…of l3Be. Pacheco and Vinh Mau [15] concluded the [10]. bReference [11], s\/2, P\/2 ordering in l2,i3Be was the same as in "B e, as did Blanchon et al [16].…”

“…Several workers [12][13][14][15][16][17] have treated l3Be as l2Be + n, and l4Be as l2Be + n + n, and have used the known 2n separation energy of l4Be(g.s.) to deduce properties of the low-lying resonances of l3Be.…”