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Energy decomposition analysis
Author(s) -
Zhao Lili,
von Hopffgarten Moritz,
Andrada Diego M.,
Frenking Gernot
Publication year - 2017
Publication title -
wiley interdisciplinary reviews: computational molecular science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.126
H-Index - 81
eISSN - 1759-0884
pISSN - 1759-0876
DOI - 10.1002/wcms.1345
Subject(s) - valence bond theory , pauli exclusion principle , atomic orbital , non bonding orbital , chemistry , molecular orbital , molecular orbital theory , molecular orbital diagram , natural bond orbital , physics , valence (chemistry) , computational chemistry , quantum mechanics , theoretical physics , chemical physics , molecule , electron
The energy decomposition analysis (EDA) is a powerful method for a quantitative interpretation of chemical bonds in terms of three major components. The instantaneous interaction energy Δ E int between two fragments A and B in a molecule A–B is partitioned in three terms, namely (1) the quasiclassical electrostatic interaction Δ E elstat between the fragments; (2) the repulsive exchange (Pauli) interaction Δ E Pauli between electrons of the two fragments having the same spin, and (3) the orbital (covalent) interaction Δ E orb which comes from the orbital relaxation and the orbital mixing between the fragments. The latter term can be decomposed into contributions of orbitals with different symmetry which makes it possible to distinguish between σ, π, and δ bonding. After a short introduction into the theoretical background of the EDA we present illustrative examples of main group and transition metal chemistry. The results show that the EDA terms can be interpreted in chemically meaningful way thus providing a bridge between quantum chemical calculations and heuristic bonding models of traditional chemistry. The extension to the EDA–Natural Orbitals for Chemical Valence (NOCV) method makes it possible to breakdown the orbital term Δ E orb into pairwise orbital contributions of the interacting fragments. The method provides a bridge between MO correlations diagrams and pairwise orbital interactions, which have been shown in the past to correlate with the structures and reactivities of molecules. There is a link between frontier orbital theory and orbital symmetry rules and the quantitative charge‐ and energy partitioning scheme that is provided by the EDA–NOCV terms. The strength of the pairwise orbital interactions can quantitatively be estimated and the associated change in the electronic structure can be visualized by plotting the deformation densities. This article is categorized under: Structure and Mechanism > Molecular Structures Electronic Structure Theory > Density Functional Theory Computer and Information Science > Visualization