O17(He3,p)F19and the structure ofF19

Abstract

Angular distributions have been measured for 18 levels of $^{19}\mathrm{F}$ populated in the reaction $^{17}\mathrm{O}$($^{3}\mathrm{He}$,$p$) at a bombarding energy of 18 MeV. Within the experimental resolution of 28 keV all levels below 5.7 MeV were observed. Nine states were excited with peak differential cross sections greater than 50 \ensuremath{\mu}b/sr, all others had maximum cross sections of less than 12 \ensuremath{\mu}b/sr. Eight of the nine strong levels are easily identifiable with ${(\mathrm{sd})}^{3}$ shell-model states. The ninth is the state at 5.11 MeV, previously assigned ${J}^{\ensuremath{\pi}}=\frac{5}{{2}^{\ensuremath{-}}}$, but suggested by the present results to have positive parity. Angular distributions were analyzed with the distorted-wave Born approximation. For the strong states, transfer amplitudes were taken from an ${(\mathrm{sd})}^{3}$ shell-model calculation. Agreement in both shape and magnitude is good. Negative-parity hole states and positive-parity core-excited states are very weakly populated, but in many cases, their angular distributions are also well fitted with admixtures of the allowed $L$ values.NUCLEAR REACTION $^{17}\mathrm{O}$($^{3}\mathrm{He}$,$p$), $E=18.0$ MeV; $^{19}\mathrm{F}$ deduced levels, $L$, $\ensuremath{\Pi}$. DWBA analysis.