The decay of the18O giant dipole resonance to excited residual nuclear states

The decay of the¹⁸O GDR to excited residual nuclear states has been examined by measuring spectra of prompt deexcitationγ-rays. The target was irradiated by bremsstrahlung with endpoint energies of 23.5 and 28 MeV. “Bremsstrahlung-weighted” integrated cross sections are given for the population of the residual nuclear states in¹⁷O,¹⁷N,¹⁶O and¹⁴C. Proton decay to excited states in¹⁷N is remarkably weak. It seems that 1p _3/2 excitations play only a minor role in the¹⁸O GDR.