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Density functional energy decomposition into one- and two-atom contributions
Vyboishchikov, Sergei F.; Salvador Sedano, Pedro; Duran i Portas, Miquel
The present work provides a generalization of Mayer's energy decomposition for the density-functional theory (DFT) case. It is shown that one- and two-atom Hartree-Fock energy components in Mayer's approach can be represented as an action of a one-atom potential VA on a one-atom density ρ A or ρ B. To treat the exchange-correlation term in the DFT energy expression in a similar way, the exchange-correlation energy density per electron is expanded into a linear combination of basis functions. Calculations carried out for a number of density functionals demonstrate that the DFT and Hartree-Fock two-atom energies agree to a reasonable extent with each other. The two-atom energies for strong covalent bonds are within the range of typical bond dissociation energies and are therefore a convenient computational tool for assessment of individual bond strength in polyatomic molecules. For nonspecific nonbonding interactions, the two-atom energies are low. They can be either repulsive or slightly attractive, but the DFT results more frequently yield small attractive values compared to the Hartree-Fock case. The hydrogen bond in the water dimer is calculated to be between the strong covalent and nonbonding interactions on the energy scale
2011-03-30
Compostos organometàl·lics
Descomposició, Mètode de
Enllaços d'hidrogen
Enllaços químics
Funcional de densitat, Teoria del
Chemical bonds
Density functionals
Decomposition method
Hydrogen bonding
Organometallic compounds
Tots els drets reservats
Article
American Institute of Physics
         

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