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Where Does Electron Correlation Lie? Some Answers from a Real Space Partition
Author(s) -
CasalzSainz José Luis,
GuevaraVela José Manuel,
Francisco Evelio,
RochaRinza Tomás,
Martín Pendás Ángel
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201700940
Subject(s) - electronic correlation , intramolecular force , ionic bonding , chemistry , partition (number theory) , cluster (spacecraft) , molecular physics , electron , atomic physics , physics , correlation , chemical physics , quantum mechanics , ion , mathematics , geometry , combinatorics , computer science , programming language
We discuss an intra‐ and interatomic partition of the electron correlation energy ( E corr ) within the interacting quantum atoms (IQA) approach at the accurate coupled cluster level with single, double, and estimated triple excitations (CCSDT(T)). This division offers a privileged window into the spatial localization of this component of the molecular energy. We show that the total molecular E corr is dominated by the intra‐atomic or intra‐fragment terms and that interatomic contributions change smoothly from short‐ to long‐range correlation (dispersion). The sign of these interatomic correlation terms differentiate between (i) mainly covalent or (ii) mainly ionic or nonbonded interactions. We propose that this feature may be used to define and examine intramolecular dispersion terms.