Geometric separation of the polarization and charge transfer components of charge sensitivities of open molecular systems

The Hilbert space approach to the internal (isoelectronic) hardness and softness kernels is presented at the global and subsystem resolutions. A separation of components due to the intramolecular polarization (P) and external charge transfer (CT) is performed by projections into the complementary subspaces spanned by the P-vectors, eigenvectors of the molecular linear response operator, and the constant CT-vector. The quantities reflecting the P–CT coupling are discussed and explicit transformations between the (P, CT)-resolved perturbations and responses are reported.