Fusion ofS32+Al27andF19+Ca40and the nucleus-nucleus potential

The measured fusion-evaporation residue excitation functions for the systems ${}_{}{}^{32}{}_{}{}^{}$S${+}^{27}$Al and ${}_{}{}^{19}{}_{}{}^{}$F${+}^{40}$Ca, were parametrized in terms of a fusion barrier radius and a critical distance. The extracted radii, from this parametrization, agree with systematics. The extracted values for the nucleus-nucleus potential agree with the potentials that are based on the liquid drop model.