Part and whole in wavefunction/DFT embedding

Dresselhaus, Thomas; Neugebauer, Johannes

doi:10.1007/s00214-015-1697-4

Cited by 41 publications

(50 citation statements)

References 77 publications

(114 reference statements)

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“…Comparable wave function overlap values were obtained in an embedded full CI calculation presented in Ref. 65. Analysis of the density difference between the self-consistent states shows that whenever a depletion of the density occurs close to hydrogen bonds, the wave function overlap increases.…”

Section: B Conventional Fdet Calculationsmentioning

confidence: 54%

“…2, i.e., ρ A -dependent embedding potential. 65 The nonorthogonality in the reported calculations originated also from other factors than the ρ A -dependence of the FDET embedding potential: ρ B -dependence of the FDET embedding potential and the use of Complete Active Space Self-Consistent Field (CASSCF) treatment of many electron problem for ρ A (⃗ r). It was shown that ρ A -dependency contributes to the overlap between the wave functions associated with different states significantly less than other factors.…”

Section: Introductionmentioning

confidence: 99%

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Orthogonality of embedded wave functions for different states in frozen-density embedding theory

Zech

Aquilante

Wesołowski

2015

The Journal of Chemical Physics

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Other than lowest-energy stationary embedded wave functions obtained in Frozen-Density Embedding Theory (FDET) [T. A. Wesolowski, Phys. Rev. A 77, 012504 (2008)] can be associated with electronic excited states but they can be mutually non-orthogonal. Although this does not violate any physical principles -embedded wave functions are only auxiliary objects used to obtain stationary densities -working with orthogonal functions has many practical advantages. In the present work, we show numerically that excitation energies obtained using conventional FDET calculations (allowing for non-orthogonality) can be obtained using embedded wave functions which are strictly orthogonal. The used method preserves the mathematical structure of FDET and self-consistency between energy, embedded wave function, and the embedding potential (they are connected through the Euler-Lagrange equations). The orthogonality is built-in through the linearization in the embedded density of the relevant components of the total energy functional. Moreover, we show formally that the differences between the expectation values of the embedded Hamiltonian are equal to the excitation energies, which is the exact result within linearized FDET. Linearized FDET is shown to be a robust approximation for a large class of reference densities. C 2015 AIP Publishing LLC. [http://dx

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Section: B Conventional Fdet Calculationsmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Orthogonality of embedded wave functions for different states in frozen-density embedding theory

Zech

Aquilante

Wesołowski

2015

The Journal of Chemical Physics

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“…A “parallel freeze‐and‐thaw” is possible using external scripting frameworks such as PyADF or the Plams (Python Library for Automating Molecular Simulations) distributed with the ADF package . Several previous studies have investigated electron densities from sDFT/FDE and reported that the final, converged densities are independent of the particular way in which the freeze‐and‐thaw procedure was carried out . Currently, the ADF internal parallelization does focus on a parallel calculation of numerical integrals rather than a parallelization over subsystems.…”

Section: Technical Aspectsmentioning

confidence: 99%

Analytical gradients for subsystem density functional theory within the slater‐function‐based amsterdam density functional program

et al. 2016

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We present a new implementation of analytical gradients for subsystem density-functional theory (sDFT) and frozen-density embedding (FDE) into the Amsterdam Density Functional program (ADF). The underlying theory and necessary expressions for the implementation are derived and discussed in detail for various FDE and sDFT setups. The parallel implementation is numerically verified and geometry optimizations with different functional combinations (LDA/TF and PW91/PW91K) are conducted and compared to reference data. Our results confirm that sDFT-LDA/TF yields good equilibrium distances for the systems studied here (mean absolute deviation: 0.09 Å) compared to reference wave-function theory results. However, sDFT-PW91/PW91k quite consistently yields smaller equilibrium distances (mean absolute deviation: 0.23 Å). The flexibility of our new implementation is demonstrated for an HCN-trimer test system, for which several different setups are applied. © 2016 Wiley Periodicals, Inc.

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“…In fact, this is a practical necessity if orbital-dependent functionals, including hybrids, shall be applied. [24][25][26] This issue also occurs for the non-additive (kinetic and exchange-correlation) kernels in linear-response TDDFT calculations of subsystem or FDE type, [27][28][29] even the choices for the XC approximations made for different subsystems may be different for pragmatic reasons, [24,30] the DFT description of (one/some of ) the subsystems may be entirely replaced by a description in terms of a (correlated) wavefunction method, [31][32][33][34][35][36] FDE and sDFT may be considered as two extreme cases concerning the relaxation of the environment density, and intermediate versions with partial relaxation can be applied. [37] In addition, there are several extensions which require to combine results from different subsystem calculations in special ways.…”

Section: Introductionmentioning

confidence: 99%

Serenity: A subsystem quantum chemistry program

et al. 2018

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We present the new quantum chemistry program Serenity. It implements a wide variety of functionalities with a focus on subsystem methodology. The modular code structure in combination with publicly available external tools and particular design concepts ensures extensibility and robustness with a focus on the needs of a subsystem program. Several important features of the program are exemplified with sample calculations with subsystem density-functional theory, potential reconstruction techniques, a projection-based embedding approach and combinations thereof with geometry optimization, semi-numerical frequency calculations and linear-response time-dependent density-functional theory. © 2018 Wiley Periodicals, Inc.

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Part and whole in wavefunction/DFT embedding

Cited by 41 publications

References 77 publications

Orthogonality of embedded wave functions for different states in frozen-density embedding theory

Orthogonality of embedded wave functions for different states in frozen-density embedding theory

Analytical gradients for subsystem density functional theory within the slater‐function‐based amsterdam density functional program

Serenity: A subsystem quantum chemistry program

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