The ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ($\gamma$,$p_0$) reaction has been studied with linearly polarized bremsstrahlung photons in and below the giant $E1\mathrm{}$ resonance. The parity of the absorbed radiation was determined from the observed azimuthal asymmetry of the emitted protons. Combined with unpolarized measurements the polarized results determine the proton decay amplitudes of the $M1\mathrm{}$ resonance at $E_x=16.2\mathrm{}$ MeV in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. The shape of the unpolarized ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ($\gamma$,$p_3$) angular distribution in the giant $E1\mathrm{}$ resonance was derived from the measured analyzing power.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$($\gamma$,$p$), $E=15-25\mathrm{}$ MeV; measured analyzing power $\theta =90\mathrm{}°$ linearly polarized bremsstrahlung; ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ dipole levels deduced $\pi$; 16.2 MeV $1^{+}$ resonance deduced $p_0$ decay amplitudes; ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ GEDR deduced $p_3$ angular distribution.

• Received 8 May 1981

DOI:https://doi.org/10.1103/PhysRevC.24.1363