quantum numbers but different values of orbital angular momentum. Spin-1 inversion is therefore the first example of coupled channel inversion in which a non-diagonal $S$-matrix is made to yield a non-diagonal potential. Apart from the general derivation, the present paper is framed for a very specific two-channel case: deuterons scattering from a spin zero nucleus with inversion determining a tensor interaction involving the non-diagonal operator $T_{\rm R}$ as given below. In spite of the rather specific nature of the present application, we believe this work opens the way to a fully general class of coupled-channel inversion situations involving the determination of a coupling potential from a non-diagonal $S$-matrix.

This paper presents in detail only those aspects of the IP inversion formalism which are connected with the specific coupled channel generalisation to spin-1 scattering. In other respects it calls upon previous publications [@ketal1; @zuev; @candm] in which the general aspects of the IP inversion procedure are described. Because of the specific application to spin-1 projectiles, we establish our notation by beginning in Section II with a brief review of basic aspects of spin-1 scattering.

An important feature of the IP $S\rightarrow V$ inversion procedure is the natural way in which it 