Assessing the impact of valence sd neutrons and protons on fusion

Experimental near-barrier fusion cross sections for F-17 + C-12 are compared to the fusion excitation functions for O-16,O-17,O-18, F-19, and Ne-20 ions on a carbon target. Normalized or reduced fusion cross sections are utilized in order to compare the different systems and account for the differing static size of the incident ions as well as changes in fusion barrier. Fusion excitation functions for the case of the mirror nuclei F-17 and O-17 with a single sd nucleon are compared. The F-17 data are also juxtaposed with nuclei involving multiple sd nucleons. Trends of the fusion cross section above the barrier beyond the expected systematic behavior are observed. These trends are interpreted as the interplay of the sd protons and neutrons. The experimental data are also compared to a widely used analytic model of near-barrier fusion, a time-dependent Hartree-Fock model, and coupled channels calculations.