The Poisson-Boltzmann equation (PBE) provides a “fast” and approximate method for calculating the effects of solvent on electrostatic interactions in the modeled system. The current solution of the PBE in CONGEN has one unique feature, it can spread the charge of each atom over the van der Waals volume which results in superior convergence properties and makes the calculation less dependent on the position of the system with respect to the grid1. In addition, CONGEN can display the partition of the Poisson-Boltzmann energy across all the atoms in the system, see the EPBE property described in Atom Properties.
The implementation provides two capabilities. First, one can perform individual electrostatic calculations on any set of atoms within the system. Second, one can replace the Coulomb electrostatic energy with the Poisson-Boltzmann energy in the context of a conformational search, see Poisson-Boltzmann Options. We hope to increase the applicability of this methodology in the future.
 R. E. Bruccoleri, “Grid Positioning Independence and the Reduction of Self-Energy in the Solution of the Poisson-Boltzmann Equation”, J. Comput. Chem. 14, 1417-1422 (1993).