Atoms-in-molecules partitioning of a molecular density

An atoms-in-a-molecule partitioning procedure, based on the minimization of the molecular grand potential, is presented. The fragments in the molecule are obtained from a set of integral operators that project the total densi ty into its components, with the sum of the fragment densities equal to the molecular density. The hard and soft acids and bases (HSAB) principle is a nalyzed generalizing a previous proof to the case where the external potent ials change. (C) 2000 John Wiley & Sons, Inc.