in the case of  according to extensive phenomenological studies, e.g.[@frickprl; @clementzphys; @frickzphys; @matoba; @ermer]. The overall conclusion is that the real part of $ V_R(r)$ predicted by the folding model is much too strong for heavy nuclei, of the right order of magnitude for light target nuclei, and actually about three times too strong for a $^4$He target.[^1] These facts, together with a large literature discussing breakup and reaction channel contributions, suggest that we have no generally applicable reliable knowledge of $V_R(r)$. There is reason to doubt even the general arguments, based on folding models, that it should be small in the interior of heavier nuclei, away from the nuclear density gradients in the surface. Such gradients define the angle between the projectile spin ${\bf s}$ and the vectorial position ${\bf r}$ of the projectile with respect to the nuclear centre, see Eq. \[eq:tensor\].

$S \rightarrow V$ inversion for spin-1 projectiles on spin-0 targets
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General background of IP inversion
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The IP method has been successful for $S_{lj} \rightarrow V(r) + {\bf l \cdot s} V_{\rm so}(r)$ inversion for spin half projectiles, and we now present its generalisation to spin-1 inversion. The only restriction is to a  tensor interaction. 