Finally, the fourth term models the second smaller correlation peak at q > 20 nm -1 . This peak originates from even shorted molecular-level length scale correlations in the sample and is most likely correlated with its higher intensity counterpart. It is parameterized in analogous way to its more intense counterpart (the third expression) with d', m' and ξpeak'. We should note, the broad peak expressions as well the OZ term merely approximate the (supra)molecular structure of the lignin. Although they correctly represent the shapes of the scattering profiles, in their mathematical form they certainly do not capture any complex structural features of macromolecules. Moreover, we use here a purely SAXS-centric formalism which assumes that electron densities are scalars, the approximation which is strictly not valid for the molecular length scales. Nevertheless, changes in parameters derived from Eq. 1 are still a valuable way to quantify the effects of processing on a lignin structure.