title: Electron correlation in the interacting quantum atoms partition via coupled-cluster lagrangian densities.
abstract: The electronic energy partition established by the Interacting Quantum Atoms (IQA) approach is an important method of wavefunction analyses which has yielded valuable insights about different phenomena in physical chemistry. Most of the IQA applications have relied upon approximations, which do not include either dynamical correlation (DC) such as Hartree-Fock (HF) or external DC like CASSCF theory. Recently, DC was included in the IQA method by means of HF/Coupled-Cluster (CC) transition densities (Chávez-Calvillo et al., Comput. Theory Chem. 2015, 1053, 90). Despite the potential utility of this approach, it has a few drawbacks, for example, it is not consistent with the calculation of CC properties different from the total electronic energy. To improve this situation, we have implemented the IQA energy partition based on CC Lagrangian one- and two-electron orbital density matrices. The development presented in this article is tested and illustrated with the H2 , LiH, H2 O, H2 S, N2 , and CO molecules for which the IQA results obtained under the consideration of (i) the CC Lagrangian, (ii) HF/CC transition densities, and (iii) HF are critically analyzed and compared. Additionally, the effect of the DC in the different components of the electronic energy in the formation of the T-shaped (H2 )2 van der Waals cluster and the bimolecular nucleophilic substitution between F(-) and CH3 F is examined. We anticipate that the approach put forward in this article will provide new understandings on subjects in physical chemistry wherein DC plays a crucial role like molecular interactions along with chemical bonding and reactivity. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán C.P. 04510, Mexico City, Mexico.
authors.forename: Fernando José
authors.initials: FJ
authors.lastname: Holguín-Gallego
authors.affiliation: School of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán C.P. 04510, Mexico City, Mexico.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Chávez-Calvillo
authors.affiliation: Department of Chemistry, Division of Natural and Exact Sciences, University of Guanajuato, C.P. 36050, Guanajuato, Guanajuato, Mexico.
authors.forename: Marco
authors.initials: M
authors.lastname: García-Revilla
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, Oviedo, Spain.
authors.forename: Evelio
authors.initials: E
authors.lastname: Francisco
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, Oviedo, Spain.
authors.forename: Ángel Martín
authors.initials: ÁM
authors.lastname: Pendás
authors.affiliation: Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán C.P. 04510, Mexico City, Mexico.
authors.forename: Tomás
authors.initials: T
authors.lastname: Rocha-Rinza
keywords: Coupled-Cluster Lagrangian Densities; Dynamical Correlation; Interacting Quantum Atoms; Quantum Chemical Topology