Ab initio no-core shell model study of neutron-rich nitrogen isotopes

Abstract

We have calculated the energy spectra for neutron-rich $^{18-22}$N isotopes using the no-core shell model. To calculate the energy spectrum we have used three different $NN$ potentials: inside non-local outside Yukawa (INOY), next-to-next-to-next-leading order (N3LO) from chiral effective field theory, and charge-dependent Bonn 2000 (CDB2K). The INOY potential is a two-body interaction but also has the effect of three-body forces at short range and a non-local character present in it. The calculations have been done at $\hbar\Omega=20$ MeV, 14 MeV, and 12 MeV using INOY, N3LO, and CDB2K potentials, respectively. We have also performed shell model calculations with the YSOX interaction. The results with the INOY interaction show good agreement with the experimental data in comparison to the other three interactions. We have also shown the occupancy of different orbitals involved corresponding to the largest model space ($N_{\rm max} = 4$) in the calculations. © 2019 The Author(s). Published by Oxford University Press on behalf of the Physical Society of Japan.