Finite-size ions in PB approach (12th of August 2013)

ions, lattice

Poisson-Boltzmann (PB) approach is the simplest description of charge interactions in solutions (e.g. of interactions between charged proteins in solutions of NaCl salt, which dissociates to Na+ i Cl- ions). It combines two very famous equations: Poisson's and Maxwell-Boltzmann's. Poisson's equation is a concise formulation of electrostatics, and Maxwell-Boltzmann's equation (i.e. distribution) is a foundation of a classical statistical mechanics.

However, a usual combination of these two equations produces a PB equation which has a drawback as it does not account for finite (and different) sizes of anions and cations (e.g.. Na+ i Cl-, depending on the salt). In a >> paper which I shortly present in this post, Marko Popović and I tried to modify a standard PB approach so to approximately include the facts (i) that the mobile ions in the solution have finite sizes and therefore prevent other ions from approaching the site they occupy, and (ii) that their sizes are not the same. The paper was published on 8th of August in Physical Review E and you can >> download it HERE.

For some papers, the illustration is secondary. The only "illustration" Marko and I made for the paper is shown in the image above, and the paper could go on without it. Sometimes, the only "illustration" a paper needs is mathematics. The equation (6) from our paper states:

equation 6

Marko Popović leaves for PhD study in Dresden next month.

Last updated on 12th of August 2013.