Auxiliary field diffusion Monte Carlo calculation of properties of oxygen isotopes

The ground state and some low-lying excited states of oxygen isotopes O18-O22 were simulated by means of auxiliary field diffusion Monte Carlo techniques. We performed the calculations by replacing the O16 core with a mean-field self-consistent potential we computed by using Skyrme interactions. The external neutrons were included in the Monte Carlo calculations, building a wave function with the orbitals computed in the self-consistent external potential. The shell considered was the 1D5/2. The NN interactions employed included tensor, spin-orbit, and three-body forces. While absolute binding energies are too deep compared with those of experimental data, the differences between the energies for nearly all isotopes and excitations are in very good agreement with the experiments. The exception is the 4+ state of the O18 isotope, which shows a larger discrepancy.