A detailed shell-model description of ${\mathrm{F}}^{18}$ and ${\mathrm{O}}^{18}$ is given for all levels of known spin and parity. New assignments are suggested. It is shown that a weak-coupling model is highly successful in reproducing the exact results.

• Received 25 August 1969

DOI:https://doi.org/10.1103/PhysRevLett.23.983