Survey ofO17excited states selectively populated by five-particle transfer reactions

Abstract

The highly selective reactions $^{12}\mathrm{C}$($^{7}\mathrm{Li}$,$d$)$^{17}\mathrm{O}$ and $^{12}\mathrm{C}$($^{6}\mathrm{Li}$,$p$)$^{17}\mathrm{O}$ have been used to populate high-lying excited states in $^{17}\mathrm{O}$ up to 16 MeV in excitation. Several of the states are newly observed, and the existence of others in a previous study of $^{12}\mathrm{C}$($^{6}\mathrm{Li}$,$p$)$^{17}\mathrm{O}$ is confirmed. The observed spectra show a clear gap of about 3 MeV, indicating an energy gap between 3p-2h and 5p-4h states in $^{17}\mathrm{O}$. Differential cross section angular distributions have been extracted from the data for both reactions and they have been compared with finite-range DWBA calculations by assuming a ``$^{5}\mathrm{He}$'' cluster transfer. Possible spins and parities are reported for states at 11.82 MeV ($7/{2}^{+}$), 12.00 MeV $(9/{2}^{+}),12.22$ MeV ($7/{2}^{\ensuremath{-}}$), and 12.42 MeV ($9/{2}^{+}$).