Assessing the impact of valence sd neutrons and protons on fusion*

Assessing the impact of valence sd neutrons and protons on fusion Experimental near-barrier fusion cross-sections for $^{17}$F + $^{12}$C are compared to the fusion excitation functions for $^{16,18}$O, $^{19}$F, and $^{20}$Ne ions on a carbon target. Comparison of the reduced fusion cross-section for the different systems accounts for the differing static size of the incident ions and changes in fusion barrier. Remaining trends of the fusion cross-section above the barrier 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.