Goodpaster, Jason D. and Ananth, Nandini and Manby, Frederick R. and Miller, Thomas F., III (2010) Exact nonadditive kinetic potentials for embedded density functional theory. Journal of Chemical Physics, 133 (8). Art. No. 084103. ISSN 0021-9606. https://resolver.caltech.edu/CaltechAUTHORS:20101011-131128803
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Abstract
We describe an embedded density functional theory (DFT) protocol in which the nonadditive kinetic energy component of the embedding potential is treated exactly. At each iteration of the Kohn–Sham equations for constrained electron density, the Zhao–Morrison–Parr constrained search method for constructing Kohn–Sham orbitals is combined with the King-Handy expression for the exact kinetic potential. We use this formally exact embedding protocol to calculate ionization energies for a series of three- and four-electron atomic systems, and the results are compared to embedded DFT calculations that utilize the Thomas–Fermi (TF) and the Thomas–Fermi–von Weisacker approximations to the kinetic energy functional. These calculations illustrate the expected breakdown due to the TF approximation for the nonadditive kinetic potential, with errors of 30%–80% in the calculated ionization energies; by contrast, the exact protocol is found to be accurate and stable. To significantly improve the convergence of the new protocol, we introduce a density-based switching function to map between the exact nonadditive kinetic potential and the TF approximation in the region of the nuclear cusp, and we demonstrate that this approximation has little effect on the accuracy of the calculated ionization energies. Finally, we describe possible extensions of the exact protocol to perform accurate embedded DFT calculations in large systems with strongly overlapping subsystem densities.
Item Type: | Article | |||||||||
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Additional Information: | © 2010 American Institute of Physics. Received 26 April 2010; accepted 12 July 2010; published online 23 August 2010. This work was partially supported by a Camille and Henry Dreyfus Foundation New Faculty Award and an Alfred P. Sloan Foundation Research Fellowship (T.F.M.). | |||||||||
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Subject Keywords: | density functional theory, ionisation potential, Thomas-Fermi model | |||||||||
Issue or Number: | 8 | |||||||||
Classification Code: | PACS: 32.50.+d; 31.15.E-; 31.15.bt | |||||||||
Record Number: | CaltechAUTHORS:20101011-131128803 | |||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20101011-131128803 | |||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
ID Code: | 20382 | |||||||||
Collection: | CaltechAUTHORS | |||||||||
Deposited By: | Tony Diaz | |||||||||
Deposited On: | 29 Nov 2010 23:55 | |||||||||
Last Modified: | 09 Mar 2020 13:18 |
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