The [formula omitted] reaction at stellar energies

Abstract

The 17 F( p,γ) 18 Ne radiative capture reaction is investigated with a two-cluster generator-coordinate method. A multi-channel description of the 18Ne wave functions as a superposition of the 17 F+ p and 14 O+α channels is used. The 17F and 14O wave functions are defined in the shell model involving s, p and sd orbitals. The model provides a good overall description of the 18Ne spectroscopy at energies typical of nova and x-ray burst processes. In particular, the 3 + 1 state, an s-wave resonance dominating the reaction rate at temperatures above 5×10 8 K, is well described. We find a proton width Γ p =21.1 keV, in good agreement with the experimental value Γ p =18.0±2 stat±1 sys keV. Its gamma width, unknown experimentally, is Γ γ =33 meV, similar to values deduced from the shell model, and used in astrophysics ( Γ γ =30±20 meV). The non-resonant ( E1) as well as the resonant contributions ( M1, E2) of the astrophysical S-factor are determined. At zero energy we find S(0)=3.5 keV-b. The corresponding 17 F( p,γ) 18 Ne reaction rate is calculated, and compared with previous approaches.