Fragment energy approach to Hartree–Fock calculations of macromolecules

Abstract

This review provides a brief introduction to energy-based fragmentation (EBF) approaches for fast and reliable quantum chemical calculations of macromolecules. The main idea of various EBF approaches is to evaluate the total energy of the target system from energies of a series of small subsystems. The theoretical foundation of these EBF approaches is attributed to the transferability of the intra- and inter-fragment energy components. Two different fragment energy approaches are introduced, but more emphasis is put on the simple EBF approach, which is applicable at both Hartree–Fock (HF) and post-HF levels. The generalized EBF approach (GEBF) is then introduced to treat charged or highly polar macromolecules. Illustrative calculations show that the GEBF approach is capable of giving reasonably reliable predictions for the total energies, optimized structures, and dipole moments or static polarizabilities, for general macromolecules.