An approximate procedure for the calculation of van der Waals and solvent-accessible surfaces areas; computing Gibbs free energies of hydration

Both geometrical and analytical steps of the new ASC procedure for the approximate computation of molecular van der Waals and solvent-accessible surface areas, were calibrated. The assigned objective was to determine best fit accurate surface values for a representative set of molecular structures. Molecular surfaces, partial atomic surfaces, as also the gradients describing surface changes as a funciton of atomic displacements are analytically described. After the validation of the ASC model, an endeavour was made to correlate experimental Gibbs free energies of hydration with partial atomic surfaces. A satisfactory correlation was obtained for a large set of organic compounds, povided that σ- and π-surface elements are introduced in addition to the traditional differentiation into polar and non-polar partial atomic surfaces