Angular Correlations in the ReactionF19(p,αγ)O16

The angular correlations between alpha-particles and gamma-rays in transitions between states of ${\mathrm{Ne}}^{20}$ and the low excited states of ${\mathrm{O}}^{16}$ have been studied at the 669-, 874-, and 935-kev resonances for proton capture in fluorine. The alpha-particle groups were separated magnetically from each other and from scattered protons. The results lead to definite assignments of spin and parity to the nuclear states involved, and show that the first four excited levels of ${\mathrm{O}}^{16}$ are consistent with a simple alpha-particle model for this nucleus. Where interference between states occurs in the reaction, the phase differences are in accord with the predictions of modern dispersion theory.