Structure of {sup 18}Ne and the breakout from the hot CNO cycle

We used the {sup 16}O({sup 3}He,{ital n}){sup 18}Ne, {sup 12}C({sup 12}C,{sup 6}He){sup 18}Ne, and {sup 20}Ne({ital p},{ital t}){sup 18}Ne reactions to study {sup 18}Ne states up to an excitation energy of 10 MeV, with emphasis on levels corresponding to {sup 14}O({alpha},{ital p}){sup 17}F and {sup 17}F({ital p},{gamma}){sup 18}Ne resonances that could strongly affect these reaction rates in hot stellar environments. Excitation energies, widths, absolute cross sections, and angular distributions were measured. We found previously unidentified states at {ital E}{sub {ital x}}=6.15{plus_minus}0.01 MeV, 7.12{plus_minus}0.02 MeV, 7.35{plus_minus}0.02 MeV, 7.62{plus_minus}0.02 MeV, 8.30{plus_minus}0.02 MeV, (8.45{plus_minus}0.03 MeV), 8.55{plus_minus}0.03 MeV, 8.94{plus_minus}0.02 MeV, and 9.58{plus_minus}0.02 MeV. We combined level width, cross section, and angular distribution data to infer {ital J}{sup {pi}} values for a number of the new levels as well as for the previously known 5.1-MeV doublet. Using information from our experiments, we recalculated the {sup 14}O({alpha},{ital p}){sup 17}F reaction rate, which constitutes a possible path out of the hot CNO cycle into the rp process and could play an important role in transforming nuclei involved in the hot CNO cycle into heavier nuclei with {ital Z}{ge}10. {copyright} {ital 1996 The American Physical Society.}