Calculation of relativistic effects in sub Coulomb heavy ion scattering

Relativistic corrections for the elastic scattering of heavy ions in the sub Coulomb regime are given. The case of two identical particles is treated especially. The deviation from the Rutherford (Mott) cross section is calculated by using the Todorov equation and the Darwin Hamiltonian, resp. It is shown, that both approches lead to the same results for small kinetic energies. Furthermore we discuss the applicability of the WKB method for calculating the phase shifts and the possibility of using a classical perturbative approach in the case of nonidentical particles.