Density embedding with constrained chemical potential

Niffenegger, K.; Oueis, Yan; Nafziger, Jonathan; Wasserman, Adam

doi:10.1080/00268976.2019.1618939

Cited by 5 publications

(4 citation statements)

References 18 publications

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“…The extension of DFT to open systems plays a crucial role in the description of charged electronic excitations [2]. More recently, it became a key ingredient in the derivation of DFT-based embedding approaches such as partition DFT [3][4][5][6][7][8][9][10], potential-functional embedding theory [11], and frozen density embedding theory for non-integer subsystems' particle numbers [12].…”

Section: Introductionmentioning

confidence: 99%

N‐centered ensemble density‐functional theory for open systems

Senjean

Fromager

2020

Int J of Quantum Chemistry

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Two (so-called left and right) variants of N -centered ensemble density-functional theory (DFT) [Senjean and Fromager, Phys. Rev. A 98, 022513 (2018)] are presented. Unlike the original formulation of the theory, these variants allow for the description of systems with a fractional electron number. While conventional DFT for open systems uses only the true electron density as basic variable, left/right N -centered ensemble DFT relies instead on (i) a fictitious ensemble density that integrates to a central (integral) number N of electrons, and (ii) a grand canonical ensemble weight α which is equal to the deviation of the true electron number from N . Within such a formalism, the infamous derivative discontinuity that appears when crossing an integral number of electrons is described exactly through the dependence in α of the left and right N -centered ensemble Hartree-exchange-correlation density functionals. Incorporating N -centered ensembles into existing density-functional embedding theories is expected to pave the way towards the in-principle-exact description of an open fragment by means of a pure-state N -electron many-body wavefunction. Work is currently in progress in this direction.

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Section: Introductionmentioning

confidence: 99%

N‐centered ensemble density‐functional theory for open systems

Senjean

Fromager

2020

Int J of Quantum Chemistry

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“…As a matter of fact, the best answer to this was already provided by chemists in the early days of chemistry: as the basic building units, functional groups or fragments in general reflect best the locality of chemical systems. As such, various fragment-based quantum chemical methods have been developed in the last decades, including mixed quantum mechanics/molecular mechanics (QM/MM), − multilayer QM/QM, − divide-and-conquer, − embedding, − and orbital- − and energy-based − fragmentation schemes, which differ mainly in how to divide the entire system into fragments and how to conquer their mutual interactions, so as to achieve high accuracy yet with low cost. For instance, in the energy-based fragmentation approaches, the electronic energy and energy-related properties of the entire system are obtained simply by assembling the fragmental values in one way or another. − The accuracy can further be improved greatly by invoking a low-level treatment of the entire system or by using a superposition of multiple fragmentation topologies .…”

Section: Introductionmentioning

confidence: 99%

iOI: An Iterative Orbital Interaction Approach for Solving the Self-Consistent Field Problem

Wang

Liu

2021

J. Chem. Theory Comput.

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An iterative orbital interaction (iOI) approach is proposed to solve, in a bottom-up fashion, the self-consistent field problem in quantum chemistry. While it belongs grossly to the family of fragment-based quantum chemical methods, iOI is distinctive in that (1) it divides and conquers not only the energy but also the wave function and that (2) the subsystem sizes are automatically determined by successively merging neighboring small subsystems until they are just enough for converging the wave function to a given accuracy. Orthonormal occupied and virtual localized molecular orbitals are obtained in a natural manner, which can be used for all post-SCF purposes.

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Section: Introductionmentioning

confidence: 99%

iOI: an Iterative Orbital Interaction Approach for Solving the Self-Consistent Field Problem

Wang

Liu

2021

Preprint

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An iterative orbital interaction (iOI) approach is proposed to solve, in a bottomup fashion, the self-consistent field problem in quantum chemistry. While it belongs grossly to the family of fragment-based quantum chemical methods, iOI is distinctive in that (1) it divides and conquers not only the energy but also the wave function, and that (2) the subsystems sizes are automatically determined by successively merging neighboring small subsystems until they are just enough for converging the wave function to a given accuracy. Orthonormal occupied and virtual localized molecular orbitals are obtained in a natural manner, which can be used for all post-SCF purposes.

show abstract

Density embedding with constrained chemical potential

Cited by 5 publications

References 18 publications

N‐centered ensemble density‐functional theory for open systems

N‐centered ensemble density‐functional theory for open systems

iOI: An Iterative Orbital Interaction Approach for Solving the Self-Consistent Field Problem

iOI: an Iterative Orbital Interaction Approach for Solving the Self-Consistent Field Problem

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