Density-Functional Theory for Fractional Particle Number: Derivative Discontinuities of the Energy

Perdew, John P.; Parr, Robert G.; Levy, Mel; Balduz, Jose L.

doi:10.1103/physrevlett.49.1691

Cited by 2,940 publications

(3,019 citation statements)

References 16 publications

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“…Moreover, the unoccupied states are found too low in energy due to the lack of the derivative discontinuity in the XC potential. 40 These two limitations lead to a substantial underestimation of the energy gap of various systems. In order to deal with the problem of SI, we apply the atomic self-interaction correction (ASIC) method, 13,58,69,70 which has been shown to improve the position of the highest occupied molecular orbital (HOMO) of molecules when compared to their gas phase I.…”

Section: Self-interaction Correctionmentioning

confidence: 99%

“…The only exception is for the HOMO level, which is equal to the negative of the ionization potential. [39][40][41] It has been demonstrated experimentally [42][43][44][45][46] that the quasi-particle energy gap, E gap QP , of a molecule, defined as the difference between its ionization potential, I, and electron affinity, A, shrinks with respect to that of the gas phase by adsorbing the molecule on a polarizable substrate. Nevertheless, the electronic structure theories usually used for such calculations can only partly account for this renormalization of the molecular energy levels when the junction is formed.…”

Section: Introductionmentioning

confidence: 99%

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Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

et al. 2014

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It is often assumed that the hydrogen atoms in the thiol groups of a benzene-1,4-dithiol dissociate when Au-benzene-1,4-dithiol-Au junctions are formed. We demonstrate, by stability and transport property calculations, that this assumption cannot be made. We show that the dissociative adsorption of methanethiol and benzene-1,4-dithiol molecules on a flat Au(111) surface is energetically unfavorable and that the activation barrier for this reaction is as high as 1 eV. For the molecule in the junction, our results show, for all electrode geometries studied, that the thiol junctions are energetically more stable than their thiolate counterparts. Due to the fact that density functional theory (DFT) within the local density approximation (LDA) underestimates the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital by several electron-volts, and that it does not capture the renormalization of the energy levels due to the image charge effect, the conductance of the Au-benzene-1,4-dithiol-Au junctions is overestimated. After taking into account corrections due to image charge effects by means of constrained-DFT calculations and electrostatic classical models, we apply a scissor operator to correct the DFT energy level positions, and calculate the transport properties of the thiol and thiolate molecular junctions as a function of the electrode separation. For the thiol junctions, we show that the conductance decreases as the electrode separation increases, whereas the opposite trend is found for the thiolate junctions. Both behaviors have been observed in experiments, therefore pointing to the possible coexistence of both thiol and thiolate junctions. Moreover, the corrected conductance values, for both thiol and thiolate, are up to two orders of magnitude smaller than those calculated with DFT-LDA.This brings the theoretical results in quantitatively good agreement with experimental data.

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Section: Self-interaction Correctionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

et al. 2014

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“…In a series of recent papers [1][2][3], two of us have developed a rigorous method for dividing a complex system into its parts based on density-functional theory [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…The underlying theory, partition-theory (PT), was used to construct a formulation of chemical reactivity theory (CRT) [3] which, for the first time, is consistent with the underlying density-functional theory [8,9] and is richer in structure than the preexisting CRT [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Partition Theory: A Very Simple Illustration

2007

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We illustrate the main features of a recently proposed method based on ensemble density functional theory to divide rigorously a complex molecular system into its parts [M.H. Cohen and A. Wasserman, J. Phys. Chem. A 111, 2229 (2007)]. The illustrative system is an analog of the hydrogen molecule for which analytic expressions for the densities of the parts (hydrogen "atoms") are found along with the "reactivity potential" that enters the theory. While previous formulations of Chemical Reactivity Theory lead to zero, or undefined, values for the chemical hardness of the isolated parts, we demonstrate they can acquire a finite and positive hardness within the present formulation.

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Radial behavior of gradient expansion approximation to atomic Fukui function and shell structure of atoms

Pacios

Gómez

1998

J. Comput. Chem.

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Density-Functional Theory for Fractional Particle Number: Derivative Discontinuities of the Energy

Cited by 2,940 publications

References 16 publications

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

Partition Theory: A Very Simple Illustration

Radial behavior of gradient expansion approximation to atomic Fukui function and shell structure of atoms

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