<scp>Δ‐SCF</scp> calculations of core electron binding energies in first‐row transition metal atoms

Jorstad, Jason V.; Xie, Tian; Morales, Carolina

doi:10.1002/qua.26881

Cited by 11 publications

(8 citation statements)

References 33 publications

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“…415 In several cases, Hartree-Fock theory proves to be more accurate than standard functionals that include correlation, even upon accounting for relativistic corrections. 414,416 This is consistent with other results indicating that the restricted open-shell (RO-)CIS method is a reasonable level of theory for M-and L-edge spectra of solidstate transition metal oxides, despite its lack of correlation effects, provided that spin-orbit corrections are included. 417 Resolution of this apparent paradox remains an open question.…”

Section: Examplessupporting

confidence: 90%

“…These errors are exposed in ∆SCF calculations of core-level electron binding energies (for x-ray photoelectron spectroscopy), where many functionals afford errors 10 eV for transition metals. 414 Even the SCAN functional, which performs well for core-excited states of second-row atoms (Table 1), affords errors of ∼ 1 eV for core-level binding energies. 415 In several cases, Hartree-Fock theory proves to be more accurate than standard functionals that include correlation, even upon accounting for relativistic corrections.…”

Section: Examplesmentioning

confidence: 98%

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Density Functional Theory for Electronic Excited States

Herbert¹

2022

Preprint

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This chapter provides a basic introduction to excited-state extensions of density functional theory (DFT), including time-dependent (TD-)DFT in both its linear-response and its explicitly time-dependent formulations. As applied to the Kohn-Sham DFT ground state, linear-response theory affords an eigenvaluetype problem for the excitation energies in a basis of singly-excited Slater determinants, and is widely known simply as "TDDFT" despite its frequency-domain formulation. This form of TDDFT is the mostly widely-used quantum-chemical method for excited states, due to a favorable combination of low cost and reasonable accuracy. The chapter surveys the accuracy of linear-response TDDFT, which is generally more sensitive to the details of the exchange-correlation functional as compared to ground-state DFT, and also describes some known systemic problems exhibited by this approach. Some of those problems can be corrected on a case-by-case basis using orbital-optimized, excited-state self-consistent field (SCF) calculations, in what is known as excited-state Kohn-Sham theory or a "∆SCF" procedure, a class of methods that includes restricted open-shell Kohn-Sham theory. Recent successes of these approaches are highlighted, including double excitations and core-level excitations. Finally, explicitly time-dependent (or "real-time") TDDFT involves propagation of the molecular orbitals in time following an external perturbation, according to the Kohn-Sham analogue of the time-dependent Schrödinger equation. The time-dependent approach has been used to model strong-field electron dynamics, and in the weak-field limit it provides a route to broadband spectra based on the time evolution of the dipole moment function. This is useful for describing high-energy excitations (as in x-ray spectroscopy) and in systems where the density of states is high, as demonstrated by a few examples.

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Section: Examplessupporting

confidence: 90%

Section: Examplesmentioning

confidence: 98%

Density Functional Theory for Electronic Excited States

Herbert¹

2022

Preprint

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“…[25][26][27][28] In recent years, ∆SCF has been used in conjunction with maximum overlap methods for computing core excitation energies and core binding energies due to the simplicity of separately optimizing the MOs of two reference states. 29,30 For weakly correlated systems, SCF determinants are often a good approximation for the ground electronic state. The reference orbitals of a good HF wavefunction are a viable guess basis for an excited SCF calculation.…”

Section: Introductionmentioning

confidence: 99%

Assessing the performance of ΔSCF and the diagonal second-order self-energy approximation for calculating vertical core excitation energies

Zamani

Hratchian

2022

The Journal of Chemical Physics

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Vertical core excitation energies are obtained using a combination of the ΔSCF method and the diagonal second-order (D2) self-energy approximation. These methods are applied to a set of neutral molecules and their anionic forms. An assessment of the results with the inclusion of relativistic effects is presented. For core excitations involving delocalized symmetry orbitals, the applied composite method improves upon the overestimation of ΔSCF by providing approximate values close to experimental K-shell transition energies. The importance of both correlation and relaxation contributions to the vertical core-excited state energies, the concept of local and non-local core orbitals, and the consequences of breaking symmetry are discussed.

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“…25,26 In recent years, ∆SCF has been used in conjunction with maximum overlap methods for computing core excitation energies and core binding energies due to the simplicity of separately optimizing the MOs of two reference states. 27,28 Through ∆SCF, much of the orbital relaxation is accounted for-quite evidently so with core excitations. What remains to be accounted for is dynamical correlation via two (or more) particle interactions.…”

Section: Introductionmentioning

confidence: 99%

Assessing the performance of ΔSCF and the diagonal second-order self-energy approximation for calculating vertical core excitation energies

Zamani

Hratchian

2022

Preprint

View full text Add to dashboard Cite

Vertical core excitation energies are obtained using a combination of the ΔSCF method and the diagonal second-order (D2) self-energy approximation. These methods are applied to a set of neutral molecules and their anionic forms. An assessment of the results with the inclusion of relativistic effects is presented. The importance of both correlation and relaxation contributions to the vertical core-excited state energies, the concept of local and non-local core orbitals, and the consequences of breaking symmetry are discussed.

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Δ‐SCF calculations of core electron binding energies in first‐row transition metal atoms

Cited by 11 publications

References 33 publications

Density Functional Theory for Electronic Excited States

Density Functional Theory for Electronic Excited States

Assessing the performance of ΔSCF and the diagonal second-order self-energy approximation for calculating vertical core excitation energies

Assessing the performance of ΔSCF and the diagonal second-order self-energy approximation for calculating vertical core excitation energies

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