Article révisé par les pairs
Résumé : We use a microscopic cluster model to investigate the C15 nucleus. Two variants are considered: a two-cluster C14+n description and a three-cluster C13+n+n approach. We show that C15 bound-state energies converge to similar values, provided that the number of C14 states is sufficient. We also study negative-parity states, and show that the three-cluster model is more appropriate. With the same nucleon-nucleon interaction, we analyze the F15 spectrum, where all known states are unbound.