A multiple-reflection expansion for heavy-ion potential scattering

New integral equation is introduced for the scattering matrix element. Its iterations generate a series, the multiple reflection expansion, each term of which corresponds to a spherical wave undergoing an ever increasing number of reflections in the potential. When no orbiting occurs, the first term in the expansion suffices. For resonance scattering however, the series is summed up in some approximation. The resulting approximation is found to be good for two selected examples of real and complex potentials.