  Properties of particle-unstable nuclei lying beyond the proton drip line can
be ascertained by considering those (usually known) properties of its mirror
neutron-rich system. We have used a multi-channel algebraic scattering theory
to map the known properties of the neutron-${}^{14}$C system to those of the
proton-${}^{14}$O one from which we deduce that the particle-unstable
${}^{15}$F will have a spectrum of two low lying broad resonances of positive
parity and, at higher excitation, three narrow negative parity ones. A key
feature is to use coupling to Pauli-hindered states in the target.
