Elastic scattering of 3He and 4He at incident energies near the coulomb barrier

The elastic scattering of ³He and ⁴He from Zr, Mo, Cd, and Te isotopes is studied at incident energies near the Coulomb barrier. Marked differences are observed between the excitation curves of ³He and ⁴He. These differences are shown to be due to a large surface absorption in the ³He scattering. A systematic study of the size parameters deduced from the present and other ⁴He experiments shows deviations from the $\text{A}\text{1}\text{3}$ law for nuclei near closed neutron shells.