The zero flux surface of the electronic wavefunction's gradient: A generalization of Bader's definition of atoms in molecules and in condensed systems

In a previous publication we derived a criterion for defining interatomic s urfaces in condensed systems based on the zero flux surface (ZFS) of the el ectronic wavefunction's gradient which holds the condition of flux zero at every point. Here this criterion is examined and physical as well as mathem atical properties are illustrated and discussed; in the light of this discu ssion we conclude that the definition illustrated in this work represents a natural extension of Bader's definition of atoms in molecules.