Skyrme random-phase approximation analysis of low-energy dipole states in oxygen isotopes

Abstract

Low-energy dipole states in oxygen isotopes are investigated using a Hartree-Fock plus random-phase approximation calculation with Skyrme interactions. We obtain the lowest energy dipole state as isoscalar dominant on the spherical ground states of $^{16--22}\mathrm{O}$, while that in $^{24}\mathrm{O}$ couples to the continuum states. This suggests that the nature of low-energy dipole mode in light nuclei changes at $N=16$.