Natural bond orbital methods

TLDR

Natural bond orbital (NBO) methods extract fundamental bonding concepts from Hartree‑Fock, DFT, and post‑HF calculations. The authors aim to introduce new features in the NBO program that address advances in ab initio computing and user demands by adding major methods, keywords, and system communication enhancements. The study presents NBO terminology and mathematical formulations for atoms and polyatomic species, and details upcoming features that add new methods, keywords, and electronic‑structure system communication. NBO analyses of diverse molecules across the periodic table demonstrate how the wavefunction can be interpreted in chemist‑friendly terms such as Lewis structures, charge, bond order, bond type, hybridization, resonance, and donor‑acceptor interactions. © 2011 John Wiley & Sons, Ltd.; article categorized under Structure and Mechanism > Molecular Structures.

Abstract

Abstract Natural bond orbital (NBO) methods encompass a suite of algorithms that enable fundamental bonding concepts to be extracted from Hartree‐Fock (HF), Density Functional Theory (DFT), and post‐HF computations. NBO terminology and general mathematical formulations for atoms and polyatomic species are presented. NBO analyses of selected molecules that span the periodic table illustrate the deciphering of the molecular wavefunction in terms commonly understood by chemists: Lewis structures, charge, bond order, bond type, hybridization, resonance, donor–acceptor interactions, etc. Upcoming features in the NBO program address ongoing advances in ab initio computing technology and burgeoning demands of its user community by introducing major new methods, keywords, and electronic structure system/NBO communication enhancements. © 2011 John Wiley & Sons, Ltd. This article is categorized under: Structure and Mechanism > Molecular Structures