Communication: Avoiding unbound anions in density functional calculations

Kim, Min Cheol; Sim, Eunji; Burke, Kieron

doi:10.1063/1.3590364

Cited by 115 publications

(160 citation statements)

References 45 publications

Supporting

Mentioning

154

Contrasting

Order By: Relevance

“…42 For electron affinities (EAs), ∆SCF predictions A N = E N −E N +1 are also found to be in agreement with experiment with the central caveat that ∆SCF predictions for EAs are only possible insofar as the system can accommodate the added electron within the approximation used; this condition on the stability of anionic states is necessary to calculate the ground-state energy of negatively charged systems. In practical terms, failure to stabilize anions is frequent within approximate DFT 43 and arises from spurious self-interaction whereby an electron can interact with itself through the nonphysical contribution from its own charge density to the effective Kohn-Sham Hamiltonian. 25 Therefore, in order to obtain reliable predictions for orbital levels (especially, for frontier donor and acceptor levels that determine the charge-transfer properties of the system), it is crucial to satisfy the following conditions: (a) the correspondence between the effective orbital levels and ∆SCF total-energy differences must be imposed; (b) the established accuracy of ∆SCF energies must be preserved; and (c) the calculations must circumvent the inability of approximate functionals to stabilize negatively charged systems.…”

Section: Present Methodsmentioning

confidence: 99%

Donor and acceptor levels of organic photovoltaic compounds from first principles

Dabo

Ferretti

Park

et al. 2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Accurate and efficient approaches to predict the optical properties of organic semiconducting compounds could accelerate the search for efficient organic photovoltaic materials. Nevertheless, predicting the optical properties of organic semiconductors has been plagued by the inaccuracy or computational cost of conventional first-principles calculations. In this work, we demonstrate that orbital-dependent density-functional theory based upon Koopmans' condition [Phys. Rev. B 82, 115121 (2010)] is apt at describing donor and acceptor levels for a wide variety of organic molecules, clusters, and oligomers within a few tenths of an electron-volt relative to experiment, which is comparable to the predictive performance of many-body perturbation theory methods at a fraction of the computational cost.

show abstract

Section: Present Methodsmentioning

confidence: 99%

Donor and acceptor levels of organic photovoltaic compounds from first principles

Dabo

Ferretti

Park

et al. 2013

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…In particular, the electron affinity (EA) of the neutral can be explored as the IP of the singly charged anion (barring geometrical relaxation). Unfortunately, for the atoms and very small molecules studied here, it is well-known [110][111][112] that with common semi-local approximations negative ions of small systems may erroneously be predicted to be unstable. However, when performing calculations with finite basis sets, as in, e.g., [113], unbound states can be artificially stabilized [114], because the basis set effectively confines the unbound electron to the vicinity of the neutral system.…”

Section: B Evaluating the Test Set -A Systematic Studymentioning

confidence: 99%

Effect of ensemble generalization on the highest-occupied Kohn-Sham eigenvalue

Kraisler

Schmidt

Kümmel

et al. 2015

The Journal of Chemical Physics

View full text Add to dashboard Cite

There are several approximations to the exchange-correlation functional in density-functional theory that accurately predict total energy-related properties of many-electron systems, such as binding energies, bond lengths, and crystal structures. Other approximations are designed to describe potential-related processes, such as charge transfer and photoemission. However, the development of a functional which can serve the two purposes simultaneously is a long-standing challenge. Trying to address it, we employ in the current work the ensemble generalization procedure proposed in Phys. Rev. Lett. 110, 126403 (2013). Focusing on the prediction of the ionization potential via the highest occupied Kohn-Sham eigenvalue, we examine a variety of exchange-correlation approximations: the local spin-density approximation, semi-local generalized gradient approximations, and global and local hybrid functionals. Results for a test set of 26 diatomic molecules and single atoms are presented. We find that the aforementioned ensemble generalization systematically improves the prediction of the ionization potential, for various systems and exchange-correlation functionals, without compromising the accuracy of total energy-related properties. We specifically examine hybrid functionals. These depend on a parameter controlling the ratio of semi-local to non-local functional components. The ionization potential obtained with ensemble-generalized functionals is found to depend only weakly on the parameter value, contrary to common experience with non-generalized hybrids, thus eliminating one aspect of the so-called 'parameter dilemma' of hybrid functionals.

show abstract

“…The calculation of electron affinities remains a challenging and controversial issue for density-functional calculations [1][2][3][4][5][6][7][8][9] . In particular, local and semi-local approximate exchangecorrelation functionals typically provide a poor description of anionic species due to large self-interaction errors (SIEs).…”

Section: Introductionmentioning

confidence: 99%

Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach

Teale

Proft

Geerlings

et al. 2014

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The essential aspects of zero-temperature grand-canonical ensemble density-functional theory are reviewed in the context of spin-density-functional theory and are used to highlight the assumption of symmetry between electron addition and subtraction that underlies the corrected Koopmans approach of Tozer and De Proft (TDP) for computing electron affinities. The issue of symmetry is then investigated in a systematic study of atomic electron affinities, comparing TDP affinities with those from a conventional Koopmans evaluation and electronic energy differences. Although it cannot compete with affinities determined from energy differences, the TDP expression yields results that are a significant improvement over those from the conventional Koopmans expression. Key insight into the results from both expressions is provided by an analysis of plots of the electronic energy as a function of the number of electrons, which highlight the extent of symmetry between addition and subtraction. The accuracy of the TDP affinities is closely related to the nature of the orbitals involved in the electron addition and subtraction, being particularly poor in cases where there is a change in principal quantum number, but relatively accurate within a single manifold of orbitals. The analysis is then extended to a consideration of the ground state Mulliken electronegativity and chemical hardness. The findings further emphasize the key role of symmetry in determining the quality of the results.

show abstract

Communication: Avoiding unbound anions in density functional calculations

Abstract: A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements

Cited by 115 publications

References 45 publications

Donor and acceptor levels of organic photovoltaic compounds from first principles

Donor and acceptor levels of organic photovoltaic compounds from first principles

Effect of ensemble generalization on the highest-occupied Kohn-Sham eigenvalue

Atomic electron affinities and the role of symmetry between electron addition and subtraction in a corrected Koopmans approach

Contact Info

Product

Resources

About