Optimization of constrained density functional theory

Teobaldi, Gilberto and O'Regan, David (2016) Optimization of constrained density functional theory. [Data Collection]

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Constrained density functional theory (cDFT) is a versatile electronic structure method that enables ground-state calculations to be performed subject to physical constraints. It thereby broadens their applicability and utility. Automated Lagrange multiplier optimisation is necessary for multiple constraints to be applied efficiently in cDFT, for it to be used in tandem with geometry optimization, or with molecular dynamics. In order to facilitate this, we comprehensively develop the connection between cDFT energy derivatives and response functions, providing a rigorous assessment of the uniqueness and character of cDFT stationary points while accounting for electronic interactions and screening. In particular, we provide a new, non-perturbative proof that stable stationary points of linear density constraints occur only at energy maxima with respect to their Lagrange multipliers. We show that multiple solutions, hysteresis, and energy discontinuities may occur in cDFT. Expressions are derived, in terms of convenient by-products of cDFT optimization, for quantities such as the dielectric function and a condition number quantifying ill-definition in multi-constraint cDFT.

Keywords: Constrained Density Functional Theory Theory of Linear Response
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Gilberto Teobaldi
Date Deposited: 12 Jul 2016 09:39
Last Modified: 12 Jul 2016 09:39
URI: http://datacat.liverpool.ac.uk/id/eprint/157

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