inversion for coupled-channel scattering.

In Ref. [@prl] we applied single step inversion to analyse real data. We note here that there are also many ways in which IP $S\rightarrow V$ inversion can contribute to understanding nucleus-nucleus interactions. Perhaps the most obvious application is the inversion of $S$-matrix elements found by phase shift analysis of experimental data. However, there are also many important applications which involve the inversion of theoretical $S$-matrix elements, i.e. elastic channel $S$ derived from coupled channel calculations, Glauber model and resonating group model calculations. The potential found in this way contains information concerning the contribution of tensor components to dynamic polarization and exchange processes to inter-nuclear potentials. For the particular case of spin-polarised deuteron and $^6$Li scattering, obvious applications include the study of the influence of reaction channels and distortion effects on the projectile-nucleus potential, especially in its non-central components. There are a number of longstanding puzzles relating to spin-polarised deuteron scattering, including the anomalously small real part of the tensor interaction, which can be studied using these methods.

Coupled-channel inversion represents a significant development in inversion techniques since a non-diagonal potential is derived from a non-diagonal $S$-matrix. Such a potential couples channels of the same conserved 