Shell-model study of boron, carbon, nitrogen and oxygen isotopes based on monopole-based-universal interaction
Cenxi Yuan, Toshio Suzuki, Takaharu Otsuka, Furong Xu, Naofumi Tsunoda
Abstract
We study boron, carbon, nitrogen and oxygen isotopes with a newly constructed shell-model Hamiltonian developed from monopole-based-universal interaction (
V
MU
). The present Hamiltonian can reproduce well the ground-state energies, energy levels, electric quadrupole properties and spin properties of these nuclei in full psd model space including
(0−3)ℏω
excitations. Especially, it correctly describes the drip lines of carbon and oxygen isotopes and the spins of the ground states of
10
B and
18
N while some former interactions such as WBP and WBT fail. We point out that the inclusion of
2ℏω
excitations is important in reproducing some of these properties. In the present
(0+2)ℏω
calculations small but constant E2 effective charges appear to work quite well. As the inclusion of the
2ℏω
model space makes rather minor change, this seems to be related to the smallness of
4
He core. Similarly, the spin g factors are very close to free values. The applicability of tensor and spin-orbit forces in free space, which are taken in the present Hamiltonian, is examined in shell model calculations.