text: To conclude, we have combined MD simulations with 
  LPT to construct simple models of electrolyte solutions 
  which account for the molecular nature of the solvent. 
  The ﬁnal result is fully analytical and it yields the ther- 
  modynamic and structural properties of the solution, in 
  agreement with the original molecular description. The 
  methodology can in principle be adapted to any molecu- 
  lar description of the system (MD simulations involving 
  interaction potentials accounting for polarization eﬀects 
  or Car-Parrinello MD simulations for example) as long 
  as the ion-ion RDF are known. It can also be generalized 
  to study interfaces. The method appears to be a promis- 
  ing approach toward the description of the speciﬁc eﬀects 
  of ions, especially for complex systems whose modeling 
  requires an analytic solution. 
  
  8 
  
  FIG. 5: (Color online) RDF obtained from MC simulations 
  (diamond), BIMSA3 (solid line), and MSA-ﬁt (dot dashed) 
  at two concentrations. 
  
  The RDF obtained within BIMSA3 are compared with 
  the MC and MSA-ﬁt results in Fig. 5. Our BIMSA3 
  model accounts for the strong molecular peak of the CIP 
  and provides the correct distances of minimal approach; 
  whereas the naive MSA-ﬁt procedure ignores the former 
  and gives poor estimates for the latter. At larger sep- 
  arations, the BIMSA3 results do not reproduce the os- 
  cillations observed in the MC simulations, but the cor- 
  responding energy oscillations in the eﬀective potentials 
  In addition, the perturbation term 
  are less than kBT . 