Abstract
The 18F(p,a)15O reaction is recognized as the predominant destruction mechanism of 18F in
novae, and its rate is therefore important for understanding 18F production in nova outbursts. We
have studied the properties of resonances in the 18F + p system using the proton-transfer reaction
18F(d, n) for the first time. We have observed fifteen 19Ne levels, five of which are below the proton
threshold, including a subthreshold state at Ex = 6.289 MeV which has significant lp = 0 strength.
The proton asymptotic normalization coefficient for this state and proton widths of states above the
proton threshold, are extracted from angular distributions. The 18F(p,a)15O S-factor and reaction
rate are re-evaluated, taking into account the subthreshold resonance and other new information
determined in this experiment.
