DESMO and ion exclusion

The above derivation of GCOSMO immediately suggests how this model can be generalized to solvents with non-zero ionic strength, using a modihed ansatz of the form 

On the other hand, the screened SS(V)PE [17] and lEF-PCM [22, 58] treatments of the LPBE lack one important feature of the original Debye-Hiickel theory, namely, a correction for the finite size of the dissolved ions. To understand this, let us recall the model problem considered by Debye and Hiickel [28], which consists of a point charge q centered in a spherical cavity of radius outside 

This potential has the form of the charge q times a screened Coulomb potential (Yukawa potential, e Jer ) multiplied by what we have termed an ion exclusion factor, y [43]. This suggests that ion exclusion might be incorporated into DESMO using an ansatz of the form [43] 

In the future, DESMO should be tested with finite ion size and compared to numerical solution of the LPBE using a cavity surface (defined by the van der Waals radii Ri) that does not coincide with the ion exclusion surface (defined by Rj + Rion)- Finite ion size has incorporated into Generalized Born models, however, via the ion exclusion factors in Eq. (11.31) [46], These models are discussed in the next section. 

The most widely used implicit solvation models in biomolecular simulations are probably the Generalized Born (GB) models [63, 79], because they are computationally inexpensive and amenable to analj ic forces. GB models posit that the electrostatic solvation energy can be expressed in the form 

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