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Molecular Binding in Post-Kohn-Sham Orbital-Free DFT

Borgoo, A.; Green, J.A.; Tozer, D.J.

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Authors

A. Borgoo

J.A. Green



Abstract

Molecular binding in post-Kohn–Sham orbital-free DFT is investigated, using noninteracting kinetic energy functionals that satisfy the uniform electron gas condition and which are inhomogeneous under density scaling. A parameter is introduced that quantifies binding, and a series of functionals are determined from fits to near-exact effective homogeneities and/or Kohn–Sham noninteracting kinetic energies. These are then used to investigate the relationship between binding and the accuracy of the effective homogeneity and noninteracting kinetic energy at the equilibrium geometry. For a series of 11 molecules, the binding broadly improves as the effective homogeneity improves, although the extent to which it improves is dependent on the accuracy of the noninteracting kinetic energy; optimal binding appears to require both to be accurate simultaneously. The use of a Thomas–Fermi–von Weizsäcker form, augmented with a second gradient correction, goes some way toward achieving this, exhibiting molecular binding on average. The findings are discussed in terms of the noninteracting kinetic potential and the Hellmann–Feynman theorem. The extent to which the functionals can reproduce the system-dependence of the near-exact effective homogeneity is quantified, and potential energy curves are presented for selected molecules. The study provides impetus for including density scaling homogeneity considerations in the design of noninteracting kinetic energy functionals.

Journal Article Type Article
Acceptance Date Jul 25, 2013
Online Publication Date Oct 30, 2013
Publication Date Dec 9, 2014
Deposit Date Dec 11, 2014
Publicly Available Date Dec 12, 2014
Journal Journal of Chemical Theory and Computation
Print ISSN 1549-9618
Electronic ISSN 1549-9626
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 10
Issue 12
Pages 5338-5345
DOI https://doi.org/10.1021/ct500670h
Public URL https://durham-repository.worktribe.com/output/1415705

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Copyright Statement
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Chemical Theory and Computation, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/ct500670h.






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