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Journal articles on the topic 'Electron density functionals'

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Published: 4 June 2021

Last updated: 19 February 2023

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1

DOBSON, J. F. "ELECTRON DENSITY FUNCTIONAL THEORY." International Journal of Modern Physics B 13, no. 05n06 (March 10, 1999): 511–23. http://dx.doi.org/10.1142/s0217979299000412.

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A brief summary is given of electronic density functional theory, including recent developments: generalized gradient methods, hybrid functionals, time dependent density functionals and excited states, van der Waals energy functionals.

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2

Savin, Andreas, and Heinz-J�rgen Flad. "Density functionals for the Yukawa electron-electron interaction." International Journal of Quantum Chemistry 56, no. 4 (November 15, 1995): 327–32. http://dx.doi.org/10.1002/qua.560560417.

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3

Reznik, I. M. "Explicit electron density functionals. Pseudowave approach." Journal of Structural Chemistry 30, no. 2 (1989): 169–72. http://dx.doi.org/10.1007/bf00761301.

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4

APARICIO, PABLO A., XAVIER LÓPEZ, and JOSEP M. POBLET. "ABILITY OF DFT CALCULATIONS TO CORRECTLY DESCRIBE REDOX POTENTIALS AND ELECTRON (DE)LOCALIZATION IN POLYOXOMETALATES." Journal of Molecular and Engineering Materials 02, no. 01 (March 2014): 1440004. http://dx.doi.org/10.1142/s2251237314400048.

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Many interesting properties of polyoxometalates (POMs) are related to their ability to reversibly accept and release electrons. The correct computational description of metal electrons in POMs is central to fully understand the implications and mechanisms related to reduced structures. We performed DFT calculations on fully oxidized [ P 2 W 18 O 62]6- and α1/α2-[ P 2 MW 17 O 62]n-( M = V , Mo ) anions, and their one-electron reduced partners. Atomic spin populations of the reduced forms reveal that pure GGA functionals, which overdelocalize the electron density by nature, cannot correctly describe the extra electron especially when competition between the localized and delocalized situations is very close in energy, namely for α2-[ P 2 MoW 17 O 62]7-. On the other hand, hybrid functionals like B3LYP or M05 can localize the electron at the correct site. Within these "well-behaved" density functionals, only the B3LYP gives the correct ordering and relative reduction energies (REs) with respect to electrochemical measurements, although the absolute values are always less exothermic than expected. At present, this is the best density functional for computing redox properties of POMs.

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5

Lee, Donghyung, and Kieron Burke. "Finding electron affinities with approximate density functionals." Molecular Physics 108, no. 19-20 (September 30, 2010): 2687–701. http://dx.doi.org/10.1080/00268976.2010.521776.

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6

Kohout, Miroslav. "Bonding indicators from electron pair density functionals." Faraday Discuss. 135 (2007): 43–54. http://dx.doi.org/10.1039/b605951c.

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7

Jin, Ye, Neil Qiang Su, Zehua Chen, and Weitao Yang. "Introductory lecture: when the density of the noninteracting reference system is not the density of the physical system in density functional theory." Faraday Discussions 224 (2020): 9–26. http://dx.doi.org/10.1039/d0fd00102c.

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We develop expressions for electron density defined through the linear response for general density functional approximations, demonstrating results for orbital functionals and for many-body perturbation theory, and explore the connections to developments in DFT.

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8

Su, Neil Qiang, Zhenyu Zhu, and Xin Xu. "Doubly hybrid density functionals that correctly describe both density and energy for atoms." Proceedings of the National Academy of Sciences 115, no. 10 (February 14, 2018): 2287–92. http://dx.doi.org/10.1073/pnas.1713047115.

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Recently, it was argued [Medvedev MG, et al. (2017) Science 355:49–52] that the development of density functional approximations (DFAs) is “straying from the path toward the exact functional.” The exact functional should yield both exact energy and density for a system of interest; nevertheless, they found that many heavily fitted functionals for molecular energies actually lead to poor electron densities of atoms. They also observed a trend that, for the nonempirical and few-parameter functionals, densities can be improved as one climbs up the first four rungs of the Jacob’s ladder of DFAs. The XYG3 type of doubly hybrid functionals (xDHs) represents a less-empirical and fewer-parameter functional on the top fifth rung, in which both the Hartree–Fock-like exchange and the second-order perturbative (MP2-like) correlation are hybridized with the low rung functionals. Here, we show that xDHs can well describe both density and energy for the same atomic set of Medvedev et al., showing that the latter trend can well be extended to the top fifth rung.

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Medvedev, Michael G., Ivan S. Bushmarinov, Jianwei Sun, John P. Perdew, and Konstantin A. Lyssenko. "Density functional theory is straying from the path toward the exact functional." Science 355, no. 6320 (January 5, 2017): 49–52. http://dx.doi.org/10.1126/science.aah5975.

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The theorems at the core of density functional theory (DFT) state that the energy of a many-electron system in its ground state is fully defined by its electron density distribution. This connection is made via the exact functional for the energy, which minimizes at the exact density. For years, DFT development focused on energies, implicitly assuming that functionals producing better energies become better approximations of the exact functional. We examined the other side of the coin: the energy-minimizing electron densities for atomic species, as produced by 128 historical and modern DFT functionals. We found that these densities became closer to the exact ones, reflecting theoretical advances, until the early 2000s, when this trend was reversed by unconstrained functionals sacrificing physical rigor for the flexibility of empirical fitting.

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10

Nagy, Szilvia, and J�nos Pipek. "Multiresolution analysis of density operators, electron density, and energy functionals." International Journal of Quantum Chemistry 84, no. 5 (2001): 523–29. http://dx.doi.org/10.1002/qua.1406.

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11

You, Zhi-Qiang, Yi-Chen Hung, and Chao-Ping Hsu. "Calculating Electron-Transfer Coupling with Density Functional Theory: The Long-Range-Corrected Density Functionals." Journal of Physical Chemistry B 119, no. 24 (January 29, 2015): 7480–90. http://dx.doi.org/10.1021/jp511216c.

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12

Hung, Linda, Chen Huang, and Emily A. Carter. "Preconditioners and Electron Density Optimization in Orbital-Free Density Functional Theory." Communications in Computational Physics 12, no. 1 (July 2012): 135–61. http://dx.doi.org/10.4208/cicp.190111.090911a.

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AbstractOrbital-free density functional theory (OFDFT) is a quantum mechanical method in which the energy of a material depends only on the electron density and ionic positions. We examine some popular algorithms for optimizing the electron density distribution in OFDFT, explaining their suitability, benchmarking their performance, and suggesting some improvements. We start by describing the constrained optimization problem that encompasses electron density optimization. Next, we discuss the line search (including Wolfe conditions) and the nonlinear conjugate gradient and truncated Newton algorithms, as implemented in our open source OFDFT code. We finally focus on preconditioners derived from OFDFT energy functionals. Newly-derived preconditioners are successful for simulation cells of all sizes without regions of low electron-density and for small simulation cells with such regions.

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13

Chattaraj, Pratim K., and Ajit J. Thakkar. "Conceptual aspects of electron densities and density functionals." Journal of Molecular Structure: THEOCHEM 943, no. 1-3 (March 2010): 1. http://dx.doi.org/10.1016/j.theochem.2010.01.025.

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14

Sharma, Prachi, Jie J. Bao, Donald G. Truhlar, and Laura Gagliardi. "Multiconfiguration Pair-Density Functional Theory." Annual Review of Physical Chemistry 72, no. 1 (April 20, 2021): 541–64. http://dx.doi.org/10.1146/annurev-physchem-090419-043839.

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Kohn-Sham density functional theory with the available exchange–correlation functionals is less accurate for strongly correlated systems, which require a multiconfigurational description as a zero-order function, than for weakly correlated systems, and available functionals of the spin densities do not accurately predict energies for many strongly correlated systems when one uses multiconfigurational wave functions with spin symmetry. Furthermore, adding a correlation functional to a multiconfigurational reference energy can lead to double counting of electron correlation. Multiconfiguration pair-density functional theory (MC-PDFT) overcomes both obstacles, the second by calculating the quantum mechanical part of the electronic energy entirely by a functional, and the first by using a functional of the total density and the on-top pair density rather than the spin densities. This allows one to calculate the energy of strongly correlated systems efficiently with a pair-density functional and a suitable multiconfigurational reference function. This article reviews MC-PDFT and related background information.

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15

Kirkpatrick, James, Brendan McMorrow, David H. P. Turban, Alexander L. Gaunt, James S. Spencer, Alexander G. D. G. Matthews, Annette Obika, et al. "Pushing the frontiers of density functionals by solving the fractional electron problem." Science 374, no. 6573 (December 10, 2021): 1385–89. http://dx.doi.org/10.1126/science.abj6511.

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Improving DFT with deep learning In the past 30 years, density functional theory (DFT) has emerged as the most widely used electronic structure method to predict the properties of various systems in chemistry, biology, and materials science. Despite a long history of successes, state-of-the-art DFT functionals have crucial limitations. In particular, significant systematic errors are observed for charge densities involving mobile charges and spins. Kirkpatrick et al . developed a framework to train a deep neural network on accurate chemical data and fractional electron constraints (see the Perspective by Perdew). The resulting functional outperforms traditional functionals on thorough benchmarks for main-group atoms and molecules. The present work offers a solution to a long-standing critical problem in DFT and demonstrates the success of combining DFT with the modern machine-learning methodology. —YS

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16

Janesko, Benjamin G. "Unification of Perdew–Zunger self-interaction correction, DFT+U, and Rung 3.5 density functionals." Journal of Chemical Physics 157, no. 15 (October 21, 2022): 151101. http://dx.doi.org/10.1063/5.0109338.

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This Communication presents a unified derivation of three different approximations used in density functional theory (DFT): the Perdew–Zunger self-interaction correction (PZSIC), the Hubbard correction DFT+U, and the Rung 3.5 density functionals. All three approximations can be derived by introducing electron self-interaction into the Kohn–Sham (KS) reference system of noninteracting electrons. The derivation uses the Adiabatic Projection formalism: one projects the electron–electron interaction operator onto certain states, introduces the projected operator into the reference system, and defines a density functional for the remainder. Projecting onto individual localized KS orbitals recovers our previous derivation of the PZSIC [B. G. Janesko, J. Phys. Chem. Lett. 13, 5698–5702 (2022)]. Projecting onto localized atom-centered orbitals recovers a variant of DFT+U. Projecting onto localized states at each point in space recovers Rung 3.5 approaches. New results include an “atomic state PZSIC” that does not require localizing the KS orbitals, a demonstration that typical Hubbard U parameters reproduce a scaled-down PZSIC, and a Rung 3.5 variant of DFT+U that does not require choosing atom-dependent states.

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17

Cioslowski, Jerzy. "Density-driven self-consistent-field method: Density functionals for electron correlation energy." Physical Review A 41, no. 7 (April 1, 1990): 3458–59. http://dx.doi.org/10.1103/physreva.41.3458.

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18

SARDROODI, JABER JAHANBIN, ALIREZA RASTKAR, NEGAR RAD YOUSEFNIA, and JAFAR AZAMAT. "COMPARATIVE INVESTIGATION OF THE EFFECT OF TYPE OF DENSITY FUNCTIONAL IN THE DETERMINATION OF GEOMETRICAL PARAMETERS IN A Cu COMPLEX." Journal of Theoretical and Computational Chemistry 12, no. 07 (November 2013): 1350066. http://dx.doi.org/10.1142/s0219633613500661.

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The effects of short-range electron correlation, long-range electron exchange, local and nonlocal parts of density, higher order gradients of density, and adding some percentage of Hartree–Fock exchange to the functional on the prediction of geometrical parameters were investigated. A copper complex namely 1,2-bis(1,4,7-triaza-1-cyclononyl) ethane copper (II) with Jahn–Teller distortion in octahedral geometry was used to evaluate the performance of 50 commonly available density functionals. The standard 3-21G basis set was used for all light elements, while pseudo potential LANL2DZ was used for the copper atom. The best bond lengths and bond angles were obtained using M05-2x and OP functionals respectively. Also in order to more accurate survey the performance of B3LYP, we used this functional with two all-electron basis sets (6-31G and 3-21G) and three basis sets involving effective core potentials (LANL2DZ/3-21G, LANL2DZ, and LACVP).

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19

Mori-Sánchez, Paula, Aron J. Cohen, and Weitao Yang. "Many-electron self-interaction error in approximate density functionals." Journal of Chemical Physics 125, no. 20 (November 28, 2006): 201102. http://dx.doi.org/10.1063/1.2403848.

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20

Jankowski, Karol, Ireneusz Grabowski, Krzysztof Nowakowski, and Jan Wasilewski. "Ab initio Correlation Effects in Density Functional Theories: An Electron-Distribution-Based Study for Neon." Collection of Czechoslovak Chemical Communications 70, no. 8 (2005): 1157–76. http://dx.doi.org/10.1135/cccc20051157.

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We have briefly reviewed the idea of studies aiming at such a bridging of the methodological gap between ab initio methods (or wave function theory (WFT)) and density functional theory (DFT) that would afford carrying over results concerning details of the structure of correlation effects from one method to the other. Special attention is paid to the problem of coverage of the WFT correlation effects by the exchange-correlation functionals of DFT. A short survey of the concept of supplementing energy-based investigations in this field by electron-density-based studies is given and illustrated by results for the Ne atom. DFT densities are generated for representatives of all four generations of presently used exchange-correlation functionals, including the recently developed orbital-dependent one. These densities are compared with WFT densities calculated at the MP2, MP3, and Brueckner determinant levels. It is found that the exchange-only parts of the local, gradient-corrected, and hybrid functionals account for the bulk of WFT correlation effects. The impact of the associated correlation functionals is very small and their physical nature is not quite clear. The situation is different for the orbital-dependent functional for which the exchange-only functional provides an almost exact description of the Hartree-Fock density. Here, the correlation effects are entirely represented by the correlation functional. Attention is also paid to the suitability of Kohn-Sham orbitals for the description of WFT correlation effects and to their presumptive similarity with Brueckner orbitals.

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21

Pustuła, Katarzyna, and Marcin Makowski. "Assessing accuracy of exchange-correlation functionals for electron affinities." Journal of Theoretical and Computational Chemistry 16, no. 06 (August 31, 2017): 1750052. http://dx.doi.org/10.1142/s0219633617500523.

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The performance of exchange-correlation (xc) functionals for the description of electron affinities of atomic and molecular systems is investigated. A benchmark set is constructed and experimental adiabatic electron affinities are compared to Density Functional Theory (DFT) predictions. The results show that although good overall accuracy may be achieved from DFT-based approaches, there still exist outliers for any of the approximations applied. Apart from employing the standard DFT models, the possibility of the optimization of range-separated xc functionals has also been tested, however, no large improvement in accuracy is observed.

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22

Ullrich, CA, and EKU Gross. "Density Functional Theory of Normal and Superconducting Electron Liquids: Explicit Functionals via the Gradient Expansion." Australian Journal of Physics 49, no. 1 (1996): 103. http://dx.doi.org/10.1071/ph960103.

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The basic idea of density functional theory is to map an interacting many-particle system on an effective non-interacting system in such a way that the ground-state densities of the two systems are identical. The non-interacting particles move in an effective local potential which is a functional of the density. The central task of density functional theory is to find good approximations for the density dependence of this local single-particle potential. An overview of recent advances in the construction of this potential (beyond the local-density approximation) will be given along with successful applications in quantum chemistry and solid state theory. We then turn to the extension of density functional theory to superconductors and first discuss the Hohenberg-Kohn-Sham-type existence theorems. In the superconducting analogue of the the normal-state Kohn-Sham formalism, a local single-particle potential is needed which now depends on two densities, the ordinary density n(r) and the anomalous density △(r,r/). As a first step towards the construction of such a potential, a gradient expansion technique for superconductors is presented and applied to calculate an approximation of the non-interacting kinetic energy functional Ts[n, △]. We also obtain a Thomas-Fermi-type variational equation for superconductors.

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23

Brütting, Moritz, Hilke Bahmann, and Stephan Kümmel. "Hybrid functionals with local range separation: Accurate atomization energies and reaction barrier heights." Journal of Chemical Physics 156, no. 10 (March 14, 2022): 104109. http://dx.doi.org/10.1063/5.0082957.

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Range-separated hybrid approximations to the exchange–correlation density functional mix exact and semi-local exchange in a position-dependent manner. In their conventional form, the range separation is controlled by a constant parameter. Turning this constant into a density functional leads to a locally space-dependent range-separation function and thus a more powerful and flexible range-separation approach. In this work, we explore the self-consistent implementation of a local range-separated hybrid, taking into account a one-electron self-interaction correction and the behavior under uniform density scaling. We discuss different forms of the local range-separation function that depend on the electron density, its gradient, and the kinetic energy density. For test sets of atomization energies, reaction barrier heights, and total energies of atoms, we demonstrate that our best model is a clear improvement over common global range-separated hybrid functionals and can compete with density functionals that contain multiple empirical parameters. Promising results for equilibrium bond lengths, harmonic vibrational frequencies, and vertical ionization potentials further underline the potential and flexibility of our approach.

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24

Domagała, Małgorzata, Mirosław Jabłoński, Alina T. Dubis, Manfred Zabel, Arno Pfitzner, and Marcin Palusiak. "Testing of Exchange-Correlation Functionals of DFT for a Reliable Description of the Electron Density Distribution in Organic Molecules." International Journal of Molecular Sciences 23, no. 23 (November 25, 2022): 14719. http://dx.doi.org/10.3390/ijms232314719.

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Researchers carrying out calculations using the DFT method face the problem of the correct choice of the exchange-correlation functional to describe the quantities they are interested in. This article deals with benchmark calculations aimed at testing various exchange-correlation functionals in terms of a reliable description of the electron density distribution in molecules. For this purpose, 30 functionals representing all rungs of Jacob’s Ladder are selected and then the values of some QTAIM-based parameters are compared with their reference equivalents obtained at the CCSD/aug-cc-pVTZ level of theory. The presented results show that the DFT method undoubtedly has the greatest problems with a reliable description of the electron density distribution in multiple strongly polar bonds, such as C=O, and bonds associated with large electron charge delocalization. The performance of the tested functionals turned out to be unsystematic. Nevertheless, in terms of a reliable general description of QTAIM-based parameters, the M11, SVWN, BHHLYP, M06-HF, and, to a slightly lesser extent, also BLYP, B3LYP, and X3LYP functionals turned out to be the worst. It is alarming to find the most popular B3LYP functional in this group. On the other hand, in the case of the electron density at the bond critical point, being the most important QTAIM-based parameter, the M06-HF functional is especially discouraged due to the very poor description of the C=O bond. On the contrary, the VSXC, M06-L, SOGGA11-X, M06-2X, MN12-SX, and, to a slightly lesser extent, also TPSS, TPSSh, and B1B95 perform well in this respect. Particularly noteworthy is the overwhelming performance of double hybrids in terms of reliable values of bond delocalization indices. The results show that there is no clear improvement in the reliability of describing the electron density distribution with climbing Jacob’s Ladder, as top-ranked double hybrids are also, in some cases, able to produce poor values compared to CCSD.

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25

ZHONG, AIGUO, and SHUBIN LIU. "VALIDITY AND INTERPRETATION OF HUND'S MULTIPLICITY RULE FOR MOLECULES: A DENSITY FUNCTIONAL STUDY." Journal of Theoretical and Computational Chemistry 04, no. 03 (September 2005): 833–47. http://dx.doi.org/10.1142/s0219633605001878.

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Validity and interpretation of Hund's multiplicity rule for one molecular system, boron hydride, is investigated from the density functional framework in the present work. Performance of a number of approximate exchange-correlaton energy denstiy functionals from LDA, GGA and hybrid models have been examined. It has been shown that all approximate functionals are able to predict the correct energy order, both adiabatically and vertically, for different spin states of the molecule, reproducing that a higher spin state from the same electronic configuration possesses a lower total energy. It is only the hybrid functionals, however, that render the picture derived for the exact density functionl theory of excited states and multiplets, that is, the validity of Hund's rule can be interpreted by the sole contribution from the outmost orbital (i.e. HOMO) of the spin states. Systematic discrepancy between the total and HOMO energy differences have been observed for both LDA and GGA forms, indicating that they are not as good in simulating the same-spin electron correlation effect as the Hartree–Fock method. We also show that it is the same as what we have found from the Hartree–Fock theory, and justification via either the nuclear-electron attraction or the exchange energy alone is not adequate to interpret the validity of the rule.

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26

NESBET, ROBERT K. "BEYOND DENSITY FUNCTIONAL THEORY: THE DOMESTICATION OF NONLOCAL POTENTIALS." Modern Physics Letters B 18, no. 02n03 (February 10, 2004): 73–82. http://dx.doi.org/10.1142/s021798490400669x.

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Due to efficient scaling with electron number N, density functional theory (DFT) is widely used for studies of large molecules and solids. Restriction of an exact mean-field theory to local potential functions has recently been questioned. This review summarizes motivation for extending current DFT to include nonlocal one-electron potentials, and proposes methodology for implementation of the theory. The theoretical model, orbital functional theory (OFT), is shown to be exact in principle for the general N-electron problem. In practice it must depend on a parametrized correlation energy functional. Functionals are proposed suitable for short-range Coulomb-cusp correlation and for long-range polarization response correlation. A linearized variational cellular method (LVCM) is proposed as a common formalism for molecules and solids. Implementation of nonlocal potentials is reduced to independent calculations for each inequivalent atomic cell.

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27

Hagiwara, Satoshi, Yasumitsu Suzuki, and Kazuyuki Watanabe. "First-Principles Study on Positron States at Li-Adsorbed Al(100) Surfaces: Effect of Electron-Positron Correlation." Defect and Diffusion Forum 373 (March 2017): 46–49. http://dx.doi.org/10.4028/www.scientific.net/ddf.373.46.

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We investigated positron states at Li-adsorbed Al(100) surfaces using \textit{ab-initio} two-component density functional theory. The results thus obtained by using semi-local electron-positron (e-p) correlation functionals with the generalized gradient approximation well reproduce the experimental results, showing that reliable e-p correlation functionals are needed to properly describe the various properties of positron surface state.

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28

Cioslowski, Jerzy, and Asiri Nanayakkara. "Electron correlation contributions to one‐electron properties from functionals of the Hartree–Fock electron density." Journal of Chemical Physics 99, no. 7 (October 1993): 5163–66. http://dx.doi.org/10.1063/1.466017.

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29

Fabiano, Eduardo, Fulvio Sarcinella, Lucian Constantin, and Fabio Della Sala. "Kinetic Energy Density Functionals Based on a Generalized Screened Coulomb Potential: Linear Response and Future Perspectives." Computation 10, no. 2 (February 15, 2022): 30. http://dx.doi.org/10.3390/computation10020030.

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We consider kinetic energy functionals that depend, beside the usual semilocal quantities (density, gradient, Laplacian of the density), on a generalized Yukawa potential, that is the screened Coulomb potential of the density raised to some power. These functionals, named Yukawa generalized gradient approximations (yGGA), are potentially efficient real-space semilocal methods that include significant non-local effects and can describe different important exact properties of the kinetic energy. In this work, we focus in particular on the linear response behavior for the homogeneous electron gas (HEG). We show that such functionals are able to reproduce the exact Lindhard function behavior with a very good accuracy, outperforming all other semilocal kinetic functionals. These theoretical advances allow us to perform a detailed analysis of a special class of yGGAs, namely the linear yGGA functionals. Thus, we show how the present approach can generalize the yGGA functionals improving the HEG linear behavior and leading to an extended formula for the kinetic functional. Moreover, testing on several jellium cluster model systems allows highlighting advantages and limitations of the linear yGGA functionals and future perspectives for the development of yGGA kinetic functionals.

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30

Su, Neil Qiang, Chen Li, and Weitao Yang. "Describing strong correlation with fractional-spin correction in density functional theory." Proceedings of the National Academy of Sciences 115, no. 39 (September 10, 2018): 9678–83. http://dx.doi.org/10.1073/pnas.1807095115.

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An effective fractional-spin correction is developed to describe static/strong correlation in density functional theory. Combined with the fractional-charge correction from recently developed localized orbital scaling correction (LOSC), a functional, the fractional-spin LOSC (FSLOSC), is proposed. FSLOSC, a correction to commonly used functional approximations, introduces the explicit derivative discontinuity and largely restores the flat-plane behavior of electronic energy at fractional charges and fractional spins. In addition to improving results from conventional functionals for the prediction of ionization potentials, electron affinities, quasiparticle spectra, and reaction barrier heights, FSLOSC properly describes the dissociation of ionic species, single bonds, and multiple bonds without breaking space or spin symmetry and corrects the spurious fractional-charge dissociation of heteroatom molecules of conventional functionals. Thus, FSLOSC demonstrates success in reducing delocalization error and including strong correlation, within low-cost density functional approximation.

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31

Ayers, Paul W. "Generalized density functional theories using the k-electron densities: Development of kinetic energy functionals." Journal of Mathematical Physics 46, no. 6 (June 2005): 062107. http://dx.doi.org/10.1063/1.1922071.

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32

Naito, Tomoya, Ryosuke Akashi, Gianluca Colò, Haozhao Liang, and Xavier Roca-Maza. "Coulomb Energy Density Functionals for Nuclear Systems: Recent Studies of Coulomb Exchange and Correlation Functionals." EPJ Web of Conferences 223 (2019): 01044. http://dx.doi.org/10.1051/epjconf/201922301044.

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The Coulomb exchange and correlation energy density functionals for electron systems are applied to nuclearsystems. It is found that the exchange functionals in the generalized gradient approximation provide agreements with the exact-Fock energy with one adjustable parameter within a few dozen keV accuracy, whereas the correlation functionals are not directly applicable to nuclear systems due to the existence of the nuclear force.

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33

Tao, Jianmin, Lin-Hui Ye, and Yuhua Duan. "Exchange-correlation energies of atoms from efficient density functionals: influence of the electron density." Journal of Physics B: Atomic, Molecular and Optical Physics 50, no. 24 (November 20, 2017): 245004. http://dx.doi.org/10.1088/1361-6455/aa95b1.

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34

Cioslowski, Jerzy, and Roberto Lopez-Boada. "Approximate one-electron density matrix functionals for the electron–electron repulsion energy from the hypervirial theorem." Journal of Chemical Physics 109, no. 11 (September 15, 1998): 4156–63. http://dx.doi.org/10.1063/1.477021.

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35

Śmiga, Szymon, Lucian A. Constantin, Fabio Della Sala, and Eduardo Fabiano. "The Role of the Reduced Laplacian Renormalization in the Kinetic Energy Functional Development." Computation 7, no. 4 (November 12, 2019): 65. http://dx.doi.org/10.3390/computation7040065.

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The Laplacian of the electronic density diverges at the nuclear cusp, which complicates the development of Laplacian-level meta-GGA (LLMGGA) kinetic energy functionals for all-electron calculations. Here, we investigate some Laplacian renormalization methods, which avoid this divergence. We developed two different LLMGGA functionals, which improve the kinetic energy or the kinetic potential. We test these KE functionals in the context of Frozen-Density-Embedding (FDE), for a large palette of non-covalently interacting molecular systems. These functionals improve over the present state-of-the-art LLMGGA functionals for the FDE calculations.

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36

Aouina, Ayoub, Matteo Gatti, and Lucia Reining. "Strategies to build functionals of the density, or functionals of Green’s functions: what can we learn?" Faraday Discussions 224 (2020): 27–55. http://dx.doi.org/10.1039/d0fd00068j.

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The present work examines ways in which model systems are used to design approximate functionals of Green's functions or of the density. It advocates efforts to select and tabulate models that are more flexible than the homogeneous electron gas.

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Elayan, Ismael A., Rishabh Gupta, and Joshua W. Hollett. "ΔNO and the complexities of electron correlation in simple hydrogen clusters." Journal of Chemical Physics 156, no. 9 (March 7, 2022): 094102. http://dx.doi.org/10.1063/5.0073227.

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The Δ natural orbital (ΔNO) two-electron density matrix (2-RDM) and energy expression are derived from a multideterminantal wave function. The approximate ΔNO 2-RDM is combined with an on-top density functional and a double-counting correction to capture electron correlation. A trust-region Newton’s method optimization algorithm for the simultaneous optimization of ΔNO orbitals and occupancies is introduced and compared to the previous iterative diagonalization algorithm. The combination of ΔNO and two different on-top density functionals, Colle–Salvetti (CS) and Opposite-spin exponential cusp and Fermi-hole correction (OF), is assessed on small hydrogen clusters and compared to density functional, single-reference coupled-cluster, and multireference perturbation theory (MRMP2) methods. The ΔNO-CS and ΔNO-OF methods outperform the single-reference methods and are comparable to MRMP2. However, there is a distinct qualitative error in the ΔNO potential energy surface for H4 compared to the exact. This discrepancy is explained through analysis of the ΔNO orbitals, occupancies, and the two-electron density.

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Harris, R. A., and Lawrence R. Pratt. "A method for systematic inclusion of electron correlation in density functionals." Journal of Chemical Physics 83, no. 8 (October 15, 1985): 4024–28. http://dx.doi.org/10.1063/1.449117.

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Bohórquez, Hugo J. "Comment on “Scaling properties of information-theoretic quantities in density functional reactivity theory” by C. Rong, T. Lu, P. W. Ayers, P. K. Chattaraj and S. Liu, Phys. Chem. Chem. Phys., 2015, 17, 4977–4988." Physical Chemistry Chemical Physics 17, no. 47 (2015): 32053–56. http://dx.doi.org/10.1039/c5cp05140a.

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The linear dependence between the density per particle σ and the electron density ρ facilitates the theoretical study of the N-scaling rules for quantum information functionals and their atomic partitions.

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Tetteh, Samuel, Ruphino Zugle, John Prosper Kwaku Adotey, and Andrews Quashie. "Electronic Spectra of ortho-Substituted Phenols: An Experimental and DFT Study." Journal of Spectroscopy 2018 (October 9, 2018): 1–10. http://dx.doi.org/10.1155/2018/4193657.

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The electronic spectra of phenol, 2-chlorophenol, 2-aminophenol, and 2-nitrophenol have been studied both experimentally and computationally. The effect of the substituents on the solvatochromic behavior of the phenols were investigated in polar protic (methanol) and aprotic (dimethyl sulfoxide (DMSO)) solvents. The spectra of 2-nitrophenol recorded the highest red shift in methanol. The observed spectral changes were investigated computationally by means of density functional theory (DFT) methods. The gas phase compounds were fully optimized using B3LYP functionals with 6-31++G(d,p) bases set. The effects of the substituents on the electron distribution in the σ-bonds as well as the natural charge on the constituent atoms were analyzed by natural bond orbital (NBO) and natural population analysis (NPA). Second-order perturbation analyses also revealed substantial delocalization of nonbonding electrons on the substituents onto the phenyl ring, thereby increasing its electron density. Full interaction map (FIM) also showed regions of varying propensities for hydrogen and halogen bonding interactions on the phenols.

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Yeh, Chia-Nan, Pei-Yin Lee, and Jeng-Da Chai. "Electronic and Optical Properties of the Narrowest Armchair Graphene Nanoribbons Studied by Density Functional Methods." Australian Journal of Chemistry 69, no. 9 (2016): 960. http://dx.doi.org/10.1071/ch16187.

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In the present study, a series of planar poly(p-phenylene) (PPP) oligomers with n phenyl rings (n = 1–20), designated as n-PP, are taken as finite-size models of the narrowest armchair graphene nanoribbons with hydrogen passivation. The singlet-triplet energy gap, vertical ionization potential, vertical electron affinity, fundamental gap, optical gap, and exciton binding energy of n-PP are calculated using Kohn-Sham density functional theory and time-dependent density functional theory with various exchange-correlation density functionals. The ground state of n-PP is shown to be singlet for all the chain lengths studied. In contrast to the lowest singlet state (i.e., the ground state) of n-PP, the lowest triplet state of n-PP and the ground states of the cation and anion of n-PP are found to exhibit some multi-reference character. Overall, the electronic and optical properties of n-PP obtained from the ωB97 and ωB97X functionals are in excellent agreement with the available experimental data.

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Ayers, Paul W., and Mel Levy. "Generalized density-functional theory: Conquering theN-representability problem with exact functionals for the electron pair density and the second-order reduced density matrix." Journal of Chemical Sciences 117, no. 5 (September 2005): 507–14. http://dx.doi.org/10.1007/bf02708356.

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43

Galván, D. H., R. Núñez-González, R. Rangel, P. Alemany, and A. Posada-Amarillas. "Assessment of Functionals for First-Principle Studies of the Structural and Electronic Properties ofδ-Bi2O3." Advances in Condensed Matter Physics 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/120294.

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Fully relativistic full-potential density functional calculations with an all-electron linearized augmented plane waves plus local orbitals method were carried out to perform a comparative study on the structural and electronic properties of the cubic oxideδ-Bi2O3phase, which is considered as one of the most promising materials in a variety of applications including fuel cells, sensors, and catalysts. Three different density functionals were used in our calculations, LDA, the GGA scheme in the parametrization of Perdew, Burke, and Ernzerhof (PBE96), and the hybrid scheme of Perdew-Wang B3PW91. The examined properties include lattice parameter, band structure and density of states, and charge density profiles. For this modification the three functionals reveal the characteristics of a metal and the existence of minigaps at high symmetry points of the band structure when spin-orbit coupling is taken into account. Density of states exhibits hybridization of Bi 6s and O 2p orbitals and the calculated charge density profiles exhibit the ionic character in the chemical bonding of this compound. The B3PW91 hybrid functional provided a better agreement with the experimental result for the lattice parameter, revealing the importance of Hartree-Fock exchange in this compound.

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Fuentealba, Patricio, Andreas Savin, Hermann Stoll, and Heinzwerner Preuss. "Electron affinities of alkaline-earth atoms by means of different density functionals." Physical Review A 40, no. 4 (August 1, 1989): 2163–65. http://dx.doi.org/10.1103/physreva.40.2163.

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Zhu, Wuming, and S. B. Trickey. "Exact density functionals for two-electron systems in an external magnetic field." Journal of Chemical Physics 125, no. 9 (September 7, 2006): 094317. http://dx.doi.org/10.1063/1.2222353.

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Mazin, I. I., and D. J. Singh. "Nonlocal density functionals and the linear response of the homogeneous electron gas." Physical Review B 57, no. 12 (March 15, 1998): 6879–83. http://dx.doi.org/10.1103/physrevb.57.6879.

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Neto, Alvaro Cunha, Francisco P. dos Santos, Alex S. Paula, Cláudio F. Tormena, and Roberto Rittner. "Density functionals for calculating NMR 1JCH coupling constants in electron-rich systems." Chemical Physics Letters 454, no. 1-3 (March 2008): 129–32. http://dx.doi.org/10.1016/j.cplett.2008.01.052.

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Brorsen, Kurt R., Patrick E. Schneider, and Sharon Hammes-Schiffer. "Alternative forms and transferability of electron-proton correlation functionals in nuclear-electronic orbital density functional theory." Journal of Chemical Physics 149, no. 4 (July 28, 2018): 044110. http://dx.doi.org/10.1063/1.5037945.

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Gibbs, Josh, Alberto Otero de la Roza, Adam Johan Bergren, and Gino A. DiLabio. "Interpretation of molecular device transport calculations." Canadian Journal of Chemistry 94, no. 12 (December 2016): 1022–27. http://dx.doi.org/10.1139/cjc-2016-0279.

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The field of molecular electronics will benefit from rational design approaches based on a complete understanding of the electronic structure of molecule-based devices. However, many computational approaches that are used to study molecular-scale devices are based on methods that have deficiencies that must be understood in order for those methods to be useful to the modeling and experimental community. Density-functional theory based methods have some well-known pitfalls that limit their application to the study of electron transport in models of molecular junction devices. Some of the impacts of these deficiencies are highlighted in this work through the use of a graphene model system and a variety of simple hydrocarbon molecules. Self-interaction error in simple functionals built from the local density approximation and the generalized gradient approximation results in very large errors in predicted absolute and relative ionization potentials. This demonstrates that electron transmission spectra predicted using these functionals should be considered with caution. We also demonstrate that care must be taken with the use of finite models for electrodes.

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Irfan, Ahmad, Mehboobali Pannipara, Abdullah G. Al-Sehemi, Muhammad Waseem Mumtaz, Mohammed A. Assiri, Aijaz Rasool Chaudhry, and Shabbir Muhammad. "Exploring the Effect of Electron Withdrawing Groups on Optoelectronic Properties of Pyrazole Derivatives as Efficient Donor and Acceptor Materials for Photovoltaic Devices." Zeitschrift für Physikalische Chemie 233, no. 11 (November 26, 2019): 1625–44. http://dx.doi.org/10.1515/zpch-2018-1166.

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Abstract Multifunctional pyrazole derivative, i.e. 3-amino-1-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-1H-benzo[f]chromene-2-carbonitrile (PBCC) has been synthesized and characterized. To shed light on various properties of interests, the ground state geometry was optimized by adopting Density Functional Theory (PBE/TZ2P). The effect of different functionals on the absorption wavelengths was studied by using Time-Domain DFT (TDDFT), e.g. GGA functional PBE, hybrid functionals B3LYP and PBE0, rang separated functionals CAM-B3LYP, LCY-PBE and CAMY-B3LYP, Dispersion Corrections PBE-D3 and B3LYP-D3. Among all these functionals PBE and PBE-D3 were found to be good choices which reproduced the absorption spectra of the PBCC. With the aim to enhance the electro-optical, charge transfer and photovoltaic properties, five new derivatives were designed by di-substituting the –F, –Cl, –Br, –COOH and –CN at benzochromene moiety. The electron injection barrier, band gap alignment and related calculated photovoltaic parameters revealed that PBCC and its newly designed derivatives would be proficient to be used in photovoltaic devices. These compounds can be used as donor materials in dye-sensitized solar cells (DSSCs) with favorable type-II band alignment. Moreover, PBCC and most of its derivatives might also be good choice as efficient acceptors with poly(dithieno[3,2-b:2,3-d]pyrrole thiophene) (PDTPr-T) and donor materials with Phenyl-C61-butyric acid methyl ester (PC61BM) in organic solar cells.

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