Symmetry between Coulomb attraction and repulsion in radiative processes

The role of analyticity in connecting attractive and repulsive orbital functions in the semiclassical theory of Coulomb excitation is reexamined in detail. It is then shown that the quantum-mechanical difference functions, which connect correspondingly the matrix elements of attractive and repulsive multipoles, can be similarly obtained by a residue calculation. The possibility of extending such relations to the relativistic Dirac case is also briefly discussed.