On the electron leak problem in orbital-free embedding calculations

Dułak, Marcin; Wesołowski, Tomasz Adam

doi:10.1063/1.2189228

Cited by 37 publications

(52 citation statements)

References 24 publications

(22 reference statements)

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“…It is worthwhile to stress at this point that the intersystem charge-flow possible in KSCED(s) calculations makes the KSCED embedding potential prone to possible flaws of the applied approximations in the relevant functionals. 51 Moreover, the KSCED(s) results approach better the basis set limit for the applied method which is based on the variational principle. The remaining deviations between the KSCED calculated and experimental parameters should be attributed to other assumptions/approximations used in the applied computational scheme: the use of average-ofconfigurations and approximations for the exchange-correlation-and nonadditive-kinetic-energy potentials.…”

Section: Resultsmentioning

confidence: 99%

“…The possibility of the intersystem charge-flow exposes the possible flaws of the approximations used in the embedding potential given in eq 2 such as an artificial charge-leak from ligands to the cation. 51 Due to the variational character of the applied method, the use of more centers in the orbital expansion leads to the results which are closer to the basis set limit. It is especially important in view of the possible extension of the present studies toward modeling the complete spectra of lanthanide centers in solids.…”

Section: Introductionmentioning

confidence: 99%

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Effect of the f-Orbital Delocalization on the Ligand-Field Splitting Energies in Lanthanide-Containing Elpasolites

Zbiri

Daul

Wesołowski

2006

J. Chem. Theory Comput.

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Abstract:The ligand-field induced splitting energies of f-levels in lanthanide-containing elpasolites are derived using the first-principles universal orbital-free embedding formalism [Wesolowski and Warshel, J. Phys. Chem. 1993, 97, 8050]. In our previous work concerning chloroelpasolite lattice (Cs 2 NaLnCl 6 ), embedded orbitals and their energies were obtained using an additional assumption concerning the localization of embedded orbitals on preselected atoms leading to rather good ligand-field parameters. In this work, the validity of the localization assumption is examined by lifting it. In variational calculations, each component of the total electron density (this of the cation and that of the ligands) spreads over the whole system. It is found that the corresponding electron densities remain localized around the cation and the ligands, respectively. The calculated splitting energies of f-orbitals in chloroelpasolites are not affected noticeably in the whole lanthanide series. The same computational procedure is used also for other elpasolite lattices (Cs 2 NaLnX 6 , where X)F, Br, and I)smaterials which have not been fabricated or for which the ligand-field splitting parameters are not available.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of the f-Orbital Delocalization on the Ligand-Field Splitting Energies in Lanthanide-Containing Elpasolites

Zbiri

Daul

Wesołowski

2006

J. Chem. Theory Comput.

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“…This finding is consistent with earlier observations that monomolecular DFT embedding is a useful strategy for mitigating charge leakage. [56][57][58] Finally, we note that Eqs. (16) and (18) can be regarded as a pairwise approximation, 31,32 such that…”

Section: Switching Between Orbital Projection and Approximation Ofmentioning

confidence: 99%

Accurate basis set truncation for wavefunction embedding

Barnes

Goodpaster

Manby³

et al. 2013

The Journal of Chemical Physics

127

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Density functional theory (DFT) provides a formally exact framework for performing embedded subsystem electronic structure calculations, including DFT-in-DFT and wavefunction theory-in-DFT descriptions. In the interest of efficiency, it is desirable to truncate the atomic orbital basis set in which the subsystem calculation is performed, thus avoiding high-order scaling with respect to the size of the MO virtual space. In this study, we extend a recently introduced projection-based embedding method [F. R. Manby, M. Stella, J. D. Goodpaster, and T. F. Miller III, J. Chem. Theory Comput. 8, 2564 (2012)] to allow for the systematic and accurate truncation of the embedded subsystem basis set. The approach is applied to both covalently and non-covalently bound test cases, including water clusters and polypeptide chains, and it is demonstrated that errors associated with basis set truncation are controllable to well within chemical accuracy. Furthermore, we show that this approach allows for switching between accurate projection-based embedding and DFT embedding with approximate kinetic energy (KE) functionals; in this sense, the approach provides a means of systematically improving upon the use of approximate KE functionals in DFT embedding. © 2013 AIP Publishing LLC. [http://dx

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“…This complex has already been used in earlier studies of the possible charge-leak problem in FDE calculations. 29,30 The structure of this complex, as it was used in the calculations, is shown in Fig. 1.…”

Section: The Failure Of the Available Approximate Kinetic-energy mentioning

confidence: 99%

“…However, Dulak and Wesolowski reinvestigated this electron-leak problem for F −¯H 2 O and Li +¯O H 2 and found that at short distances it is of no importance for the calculation of the ground-state density and interaction energies. 30 On the other hand, in calculations on CO 2¯X ͑X v He, Ne, Ar, Kr, Xe, and Hg͒ van der Waals complexes, it was found that for the complexes containing the heavier rare gases or mercury the dipole moment is overestimated if basis functions on the frozen system are included. This has also been attributed to the fact that close to the nuclei the PW91k kinetic-energy functional is not able to compensate the large nuclear attraction.…”

Section: Introductionmentioning

confidence: 99%

High-accuracy calculation of nuclear quadrupole moments of atomic halogens

Yakobi

Eliav

Visscher

et al. 2007

The Journal of Chemical Physics

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We have investigated the functional derivative of the nonadditive kinetic-energy bifunctional, which appears in the embedding potential that is used in the frozen-density embedding formalism, in the limit that the separation of the subsystems is large. We have derived an exact expression for this kinetic-energy component of the embedding potential and have applied this expression to deduce its exact form in this limit. Comparing to the approximations currently in use, we find that while these approximations are correct at the nonfrozen subsystem, they fail completely at the frozen subsystem. Using test calculations on two model systems, a H 2 O¯Li + complex and a cluster of aminocoumarin C151 surrounded by 30 water molecules, we show that this failure leads to a wrong description of unoccupied orbitals, which can lead to convergence problems caused by too low-lying unoccupied orbitals and which can further have serious consequences for the calculation of response properties. Based on our results, a simple correction is proposed, and we show that this correction is able to fix the observed problems for the model systems studied.

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On the electron leak problem in orbital-free embedding calculations

Cited by 37 publications

References 24 publications

Effect of the f-Orbital Delocalization on the Ligand-Field Splitting Energies in Lanthanide-Containing Elpasolites

Effect of the f-Orbital Delocalization on the Ligand-Field Splitting Energies in Lanthanide-Containing Elpasolites

Accurate basis set truncation for wavefunction embedding

High-accuracy calculation of nuclear quadrupole moments of atomic halogens

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