Solv: An Alternative Continuum Model Implementation Based on Fixed Atomic Charges, Scaled Particle Theory, and the Atom-Atom Potential Method

An alternative continuum model implementation is reported.Theelectrostatic contribution to the solvation Gibbs free energy utilizesthe noniterative conductor-like screening model of Vyboishchikov andVoityuk (DOI: 10.1002/jcc.26531) based on the fixed partial atomiccharges. The nonelectrostatic solute-solvent dispersion-repulsionenergy is calculated through the Caillet-Claverie atom-atompotential method employing the grid-based approach. The nonelectrostaticcavitation energy is computed within the scaled particle theory (SPT)formalism with the solute hard-sphere radius obtained via the Pierotti-Claverie(PC) scheme, from the solute molecular surface (SPT-S) or volume (SPT-V).The solvent hard-sphere radius is derived through the fitting to theexperimental total solvation free energies of 2530 neutral speciesin 92 solvents. Application of the model to reproduce both the absoluteand relative (reaction net) solvation free energies indicates thatthe SPT-V approach based on the CM5 charges is the best performer.The method is suggested for the solvation free energy calculationin the nonaqueous solvents.

Automated summary

This study presents an alternative continuum model implementation for calculating solvation free energy. The electrostatic contribution is calculated using the noniterative conductor-like screening model, whereas the non-electrostatic interactions are computed through the Caillet-Claverie atom-atom potential method. The method shows good performance in reproducing solvation free energies in both absolute and relative cases, making it suitable for nonaqueous solvents.