Differential cross sections in the impact parameter treatment of charge transfer

The differential cross section for electron capture in the semiclassical impact parameter treatment is written in terms of a classical elastic differential cross section multiplied by an electron transfer probability. The relationship between the phase of the transfer amplitude and the classical differential cross section is stressed. Comparison is made between the exact semiclassical result and the method described above, for the case where the internuclear interaction is purely Coulombic. The effect of electron screening in modifying the classical elastic differential cross section is also illustrated.