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Title: The density matrix functional approach to electron correlation: Dynamic and nondynamic correlation along the full dissociation coordinate

For chemistry an accurate description of bond weakening and breaking is vital. The great advantage of density matrix functionals, as opposed to density functionals, is their ability to describe such processes since they naturally cover both nondynamical and dynamical correlation. This is obvious in the Löwdin-Shull functional, the exact natural orbital functional for two-electron systems. We present in this paper extensions of this functional for the breaking of a single electron pair bond in N-electron molecules, using LiH, BeH{sup +}, and Li{sub 2} molecules as prototypes. Attention is given to the proper formulation of the functional in terms of not just J and K integrals but also the two-electron L integrals (K integrals with a different distribution of the complex conjugation of the orbitals), which is crucial for the calculation of response functions. Accurate energy curves are obtained with extended Löwdin-Shull functionals along the complete dissociation coordinate using full CI calculations as benchmark.
Authors:
; ;  [1] ;  [2] ;  [1] ;  [2] ;  [3]
  1. Section Theoretical Chemistry, VU University, Amsterdam (Netherlands)
  2. (Korea, Republic of)
  3. (Saudi Arabia)
Publication Date:
OSTI Identifier:
22304264
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 21; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DENSITY MATRIX; DIAGRAMS; DISSOCIATION; ELECTRON CORRELATION; ELECTRON PAIRS; ELECTRONS; FUNCTIONALS; LITHIUM HYDRIDES; MOLECULES; RESPONSE FUNCTIONS