Correcting density-driven errors in projection-based embedding

Robert C R Pennifold, Simon J. Bennie, Thomas F. Miller, Frederick R. Manby*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

10 Citations (Scopus)
209 Downloads (Pure)

Abstract

Projection-based embedding provides a simple and numerically robust framework for multiscale wavefunction-in-density-functional-theory (WF-in-DFT) calculations. The approach works well when the approximate DFT is sufficiently accurate to describe the energetics of the low-level subsystem and the coupling between subsystems. It is also necessary that the low-level DFT produces a qualitatively reasonable description of the total density, and in this work, we study model systems where delocalization error prevents this from being the case. We find substantial errors in embedding calculations on open-shell doublet systems in which self-interaction errors cause spurious delocalization of the singly occupied orbital. We propose a solution to this error by evaluating the DFT energy using a more accurate self-consistent density, such as that of Hartree-Fock (HF) theory. These so-called WF-in-(HF-DFT) calculations show excellent convergence towards full-system wavefunction calculations.

Original languageEnglish
Article number084113
Number of pages7
JournalJournal of Chemical Physics
Volume146
Issue number8
Early online date1 Feb 2017
DOIs
Publication statusPublished - 28 Feb 2017

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