Wave Function and Density Functional Theory Studies of Dihydrogen Complexes

Fabiano, Eduardo; Constantin, Lucian A.; Sala, Fabio Della

doi:10.1021/ct500350n

Cited by 28 publications

(30 citation statements)

References 125 publications

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“…interfaces) the E g parameter must be spatially dependent, as shown for example in Refs. 61,115,121 . Such a KE functional, will be more complicated than the simple KGAP, but we expect it to be very accurate.…”

Section: Discussionmentioning

confidence: 99%

“…(5) but the LR of the jellium-withgap model 61,104 . This is an important generalization of the uniform electron gas, that has already been used to have qualitative and quantitative insight for semiconductors [104][105][106][107][108] , to develop an XC kernel for the optical properties of materials 109 , and to construct accurate functionals for the ground-state DFT [110][111][112][113][114][115] . Recently, the KE gradient expansion of the jellium-withgap has also been derived and used in the construction of semilocal KE functionals 61 .…”

Section: Introductionmentioning

confidence: 99%

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Nonlocal kinetic energy functional from the jellium-with-gap model: Applications to orbital-free density functional theory

2018

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Orbital-Free Density Functional Theory (OF-DFT) promises to describe the electronic structure of very large quantum systems, being its computational cost linear with the system size. However, the OF-DFT accuracy strongly depends on the approximation made for the kinetic energy (KE) functional. To date, the most accurate KE functionals are non-local functionals based on the linear-response kernel of the homogeneous electron gas, i.e. the jellium model. Here, we use the linear-response kernel of the jellium-with-gap model, to construct a simple non-local KE functional (named KGAP) which depends on the band gap energy. In the limit of vanishing energy-gap (i.e. in the case of metals), the KGAP is equivalent to the Smargiassi-Madden (SM) functional, which is accurate for metals. For a series of semiconductors (with different energy-gaps), the KGAP performs much better than SM, and results are close to the state-of-the-art functionals with complicated density-dependent kernels.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nonlocal kinetic energy functional from the jellium-with-gap model: Applications to orbital-free density functional theory

2018

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“…[272] and Figure 5 of Ref. [277]). This fact causes abrupt variations in the functional which are responsible for the integration problems.…”

Section: Integration Grid Problems For Molecular Systemsmentioning

confidence: 93%

“…hydrogen-bond (HB6 [357] ), dipole-dipole (DI6 [357] ), dihydrogen-bond (DHB23 [277] ), charge-transfer (CT7 [357] ), and p2p-stacking (pp5 [357] )…”

Section: Noncovalent Interactions This Group Tests Interaction Energmentioning

confidence: 99%

Kinetic‐energy‐density dependent semilocal exchange‐correlation functionals

Sala

Fabiano

Constantin

2016

Int J of Quantum Chemistry

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We present the theory of semilocal exchange-correlation (XC) energy functionals which depend on the Kohn-Sham kinetic energy density (KED), including the relevant class of meta-generalized gradient approximation (meta-GGA) functionals. Thanks to the KED ingredient, meta-GGA functionals can satisfy different exact constraints for XC energy and can be made one-electron selfcorrelation free. This leads to a better accuracy over a wider range of properties with respect to GGAs, often reaching the accuracy of hybrid functionals, but at much reduced computational cost.An extensive survey of the relevant literature on existing KED dependent XC functionals is provided, considering nonempirical, semi-empirical, and fully empirical ones. A deeper analysis and a wide benchmark are presented for functionals derived considering only exact constraints and parameters obtained from model and/or atomic systems. K E Y W O R D Sdensity functional theory, kinetic energy, meta-GGA | I N T R O D U C T I O NKohn-Sham (KS)-density functional theory (DFT) [1][2][3][4][5] is nowadays one of the most popular computational approaches in quantum chemistry, solid-state physics, and materials science. [6][7][8][9][10][11] While the ground-state description of a real system of interacting electrons requires a complicate N-electron wavefunction, in KS-DFT this is mapped onto an auxiliary system of noninteracting electrons having the same ground-state density, which can be easily described using N single-particle KS orbitals. [1,2] The correspondence between the many-electron problem and the KS system is in principle exact [1,3] and it is based on the so called exchange-correlation (XC) energy functional, which collects all the quantum electron-electron interaction terms beyond the Hartree one. [12] Within the constrained-search formalism, [13] the XC energy functional is:E xc ½q 5 min W!q hWjT 1V ee jWi2T s ½q 2J½q 5E x ½q 1U c ½q 1T c ½q ;(1) where W is an N-electron ground-state wavefunction yielding the electron density q,T is the kinetic energy (KE) operator,V ee is the electron-electron interaction operator, T s is the KE of the noninteracting system, J is the Coulomb energy, E x is the exact exchange energy, and U c and T c represent, respectively, the potential and the kinetic contributions to the DFT correlation energy E c 5U c 1T c . The important point of Equation1 is that it is an universal functional of the electron density. However, its explicit functional form is not known, and any practical realization of KS-DFT is based on an approximated XC functional. The latter determines in practice the overall accuracy of the KS-DFT calculation.The study of the exact properties of the XC energy functional as well as the development of new and improved approximations have been hot research topics in DFT for more than three decades, and a large number of XC approximations has been proposed. [12,14,15] The different XC functionals are usually classified, according to their complexity, on the so called Jacob's ladder of DFT [14,16] whic...

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“…The lowest rung of the ladder includes the local, semilocal generalized‐gradient‐approximation (GGA), and meta‐GGA functionals, which depend only on (semi)local quantities such as the electron density, its spatial derivatives (gradient and Laplacian), and the positive‐defined kinetic energy density . These density‐based DFAs are very efficient, due to their local nature, but often encounter important limitations outside well defined application boundaries . Improvement is obtained considering XC functionals depending also on the KS orbitals: either only occupied orbitals (e.g., in the case of hybrid functionals) or both occupied and virtual orbitals as well as KS eigenvalues (e.g., when ab initio ‐like correlation is included) .…”

Section: Introductionmentioning

confidence: 99%

Accurate Kohn–Sham ionization potentials from scaled‐opposite‐spin second‐order optimized effective potential methods

et al. 2016

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One important property of Kohn-Sham (KS) density functional theory is the exact equality of the energy of the highest occupied KS orbital (HOMO) with the negative ionization potential of the system. This exact feature is out of reach for standard density-dependent semilocal functionals. Conversely, accurate results can be obtained using orbital-dependent functionals in the optimized effective potential (OEP) approach. In this article, we investigate the performance, in this context, of some advanced OEP methods, with special emphasis on the recently proposed scaled-opposite-spin OEP functional. Moreover, we analyze the impact of the so-called HOMO condition on the final quality of the HOMO energy. Results are compared to reference data obtained at the CCSD(T) level of theory. © 2016 Wiley Periodicals, Inc.

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Wave Function and Density Functional Theory Studies of Dihydrogen Complexes

Cited by 28 publications

References 125 publications

Nonlocal kinetic energy functional from the jellium-with-gap model: Applications to orbital-free density functional theory

Nonlocal kinetic energy functional from the jellium-with-gap model: Applications to orbital-free density functional theory

Kinetic‐energy‐density dependent semilocal exchange‐correlation functionals

Accurate Kohn–Sham ionization potentials from scaled‐opposite‐spin second‐order optimized effective potential methods

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