Alpha-particle and triton cluster states in 19F

Abstract

We calculate the energies and other properties of three- and four-particle cluster states in the nuclei 19F and 19Ne, treated as eigenstat es of a local cluster-core potential. The potential we consider is a symmetrized Saxon-Woods well which has the advantage that a single value of the potential depth can generate rotational spectra of levels with different values of orbital angular momentum L; in this respect, it is very similar to the folding potentials which have been used in previous cluster calculations. We discuss the cluster states in the light of recent three- and four-particle heavy ion transfer reactions and studies of the electromagnetic decay properties of bound and continuum states. Most of the states observed to be strongly populated in the transfer experiments can be unambiguously assigned to cluster bands based on 16O + t and 15N + α configurations with various angular momenta and node numbers. Some evidence for mixing between triton and alpha configurations exists and is discussed. We also calculate the electromagnetic properties of the cluster states and find that, with few exceptions, they are in good agreement with the experimental data. Some El transitions are predicted to be very large, contrary to existing experiments, and new experiments are proposed to investigate this discrepancy.