Scattering by an r/sup -2n/ potential in the Born approximation and application to dipole--quadrupole scattering

By using the Born approximation, an analytic formula is derived for the phase shifts δL for scattering by a potential with an r−2n tail. The low-energy properties of the phase shifts are discussed, and an expansion of tan δL in powers of k is presented. The dipole-quadrupole r−8 potential is discussed as a special case.