GCOSMO model

In addition to SMx and the cluster-continuum model, other continuum models have also been used to study reactions in liquids, including the polarized continuum model [133-135] (PCM), the conductor-like screening model (COSMO [136] and COSMO-RS [137,138]), the generalized COSMO [139] (GCOSMO) model, conductorlike PCM [140] (CPCM), and isodensity PCM [141] (IPCM). 

PCM are explicated in Table 11.1. Also listed in this table are the forms of K and R for the so-called conductor-like model, C-PCM [25]. This model is considerably simpler in that the matrix D is absent. C-PCM is identical to the generalized conductor-iike screening modei (GCOSMO) [78], and almost identical to the original COSMO [37]. (G]COSMO was introduced prior to SS(V)PE/1EF-PCM, based on ad hoc arguments and designed to achieve the correct oo limit. We... 

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... 

Truong, T. N., Nguyen, U. N., and Stefanovich, E. V. (1996). Generalized conductor-like screening model (GCOSMO) for solvation An assessment of its accuracy and applicability, Int ]. Quantum Chem. Symp. 60, pp. 1615-1622. 

Here, we note only that the properties computed from these models are extremely sensitive to how the molecular cavity (solute/continuum interface) is constructed, and that nonelectrostatic solvation effects are typically (though not always ) neglected in the PCMs such as COSMO, GCOSMO, lEF-PCM, and SS(V)PE that are derived from Poisson s equation for continuum electrostatics. In contrast, such effects are built into the empirical SMx models and are crucial to accurate prediction of solvation free energies. " It is unclear how the neglect of nonelectrostatic effects might impact the calculation of anion VDEs cavitation effect should cancel, but dispersion effects may not, as the anion is intrinsically more polarizable. One may hope that these effects will disappear if a sufficiently large number of explicit solvent molecules is included as part of the QM solute. 

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