text: trapolating the original potential at the barrier separat- 
  ing pairs from free ions (as shown in Fig. 3). We assume 
  that the interaction potential is averaged over the rota- 
  tional degrees of freedom of the CIP and thus pairwise 
  additive. Hereafter, the quantities referring to such a 
  three-component model are written with a tilda symbol. 
  The short-range potentials involving the pair can be de- 
  rived, in the inﬁnite dilution limit, from an average of 
  the contributing ion interactions. In Fourier space, 