Calculating partial charges for interatomic coulombic interactions

[Hypatio]

I want to understand how to compute (or find a database for) partial charges, which I can then apply to calculating coulombic interactions.

From http://www.chemaxon.com/marvin/help/calculations/charge.html, it is said that electronegativity is related to the partial charge by a quadratic function, but it seems to not be fully explained.

How would I compute partial charges? Ultimately, I want to calculate interactions for all pairs between Si,Fe,Mg, Ca, and O, or at least between O and these cations.

Thanks in advance.

 

[Useful nucleus]

There is no one unique way to calculate partial charges. Quantum chemists use Mulliken chagre analysis. Solid state physicists and/or materials scientists can rely on Born effective charges or Bader charge analysis. Molecular dynamics simulations folks would fit the partial charges to reproduce certain desired properties (dielectric constant, lattice parameters, etc...). Choose the method that fits your needs the best.