Electron gas predictions of interatomic potentials tested by <i>ab initio</i> calculations

Wood, C.P.; Pyper, N.C.

doi:10.1080/00268978100102131

Cited by 30 publications

(12 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a system of finite extent, it was shown 50,51 that this unwanted self-exchange could be eliminated by multiplying the exchange energy by a correction factor ␥͑N͒ depending on the effective number ͑N͒ of electrons contributing to the interatomic interaction. It was further shown [52][53][54] that, for the interaction of two mononuclear species, the effective number N should be taken to be the total number of outermost electrons on both species, this being 16 for the interaction of two mononuclear species of s 2 p 6 outermost electronic configurations.…”

Section: The Uncorrelated Short-range Ion-nanotube Interactionsmentioning

confidence: 99%

Theoretical study of the structures and electronic properties of all-surface KI and CsI nanocrystals encapsulated in single walled carbon nanotubes

Bichoutskaia

Pyper

2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

The structural and electronic properties of all-surface KI and CsI crystals encapsulated in single-walled carbon nanotubes are investigated theoretically with an ionic and atomistic approach using the GULP program. The short-range interactions, derived from Dirac-Fock wavefunctions, were augmented with damped dipole-dipole and dipole-quadrupole dispersive attractions. The uncorrelated interionic interactions computed using the relativistic crystal ion and relativistic integral programs accounted for anion in-crystal modifications while being exact given the ion wavefunctions. All the short-range correlation energies and the uncorrelated interactions between the ions and carbon atoms were computed using the density functional theory of a uniform electron gas of infinite extent. Unphysical self-interactions were removed by scaling the exchange interaction with a Rae factor derived from a study of the adsorption of noble gases on graphite. The predictions for the nonencapsulated crystals agreed well with those previously derived from a global analytic theory based on the Born model. This provided a good description of the contraction of the interplane distance (b) relative to the separation (R(e)) in the rocksalt structured bulk material although failing to account for the observed dilation of the intraplane ionic separations (a). Introduction of the interactions with the nanotube wall, including the ion-nanotube dispersive attractions, increased the predicted a values although these were still significantly smaller than experiment. The predicted b separations were reduced compared with those for the nonencapsulated crystals to values significantly less than observed. It is explained why introducing any ion-nanotube interactions that are sufficiently attractive as to reproduce the experimental a values must significantly underestimate the b separations. The partial transfer of anion electrons to the nanotube carbon atoms, not considered hitherto, was described by decomposing the intra-atomic interactions of both the nanotube pi- and the iodide 5p-electrons into an effective one-electron term plus the repulsion between electrons in the same orbital. These energies were derived from electronic structure computations with the additional interspecies electrostatic repulsions derived from the GULP program. Structural predictions are presented as a function of the number (n) of electrons transferred from each anion. For both KI and CsI, the structure predicted by that computation, which minimized the total energy, in contrast to the other calculations, agreed well with experiment reproducing both the significant dilation of a and the smaller contraction of b. The respective n values (n(t)) predicting the lowest energies are 0.278 and 0.285. These results are supported by comparing the experimental frequencies of Raman modes attributable to vibrations of nanotubes encapsulating KI with the corresponding frequencies for systems where independently known numbers of electrons were transferred to the nanotubes. In both the enc...

show abstract

Section: The Uncorrelated Short-range Ion-nanotube Interactionsmentioning

confidence: 99%

Theoretical study of the structures and electronic properties of all-surface KI and CsI nanocrystals encapsulated in single walled carbon nanotubes

Bichoutskaia

Pyper

2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…Corrections were added to the non-self consistent GK calculations to account for self-interaction errors [WP81] and to include induction effects and dispersion forces [H84]. The first self-consistent versions of the GK model were also proposed [SS86].…”

Section: 'Smentioning

confidence: 99%

The Importance of Being Inconsistent

Wasserman

Nafziger

Jiang

et al. 2017

Annu. Rev. Phys. Chem.

116

156

View full text Add to dashboard Cite

We review the role of self-consistency in density functional theory. We apply a recent analysis to both Kohn-Sham and orbital-free DFT, as well as to Partition-DFT, which generalizes all aspects of standard DFT. In each case, the analysis distinguishes between errors in approximate functionals versus errors in the self-consistent density. This yields insights into the origins of many errors in DFT calculations, especially those often attributed to self-interaction or delocalization error. In many classes of problems, errors can be substantially reduced by using 'better' densities. We review the history of these approaches, many of their applications, and give simple pedagogical examples.

show abstract

“…The actual tests used the electron-gas method in its most satisfactory modification [12]. However, for the noble gas dimers, this was shown to reproduce the repulsion predicted using unmodified atomic wavefunctions [29]. The overestimation of the repulsion predicted using unmodified atomic wavefunctions will tend to cancel that of the magnitude of the dispersion evaluated without damping.…”

Section: The Predictions Of the Hfscdd Methodsmentioning

confidence: 99%

The noble gas dimers as a probe of the energetic contributions of dispersion and short-range electron correlation in weakly bound systems

Housden

Pyper

2007

Molecular Physics

View full text Add to dashboard Cite

Electron gas predictions of interatomic potentials tested by ab initio calculations

Cited by 30 publications

References 20 publications

Theoretical study of the structures and electronic properties of all-surface KI and CsI nanocrystals encapsulated in single walled carbon nanotubes

Theoretical study of the structures and electronic properties of all-surface KI and CsI nanocrystals encapsulated in single walled carbon nanotubes

The Importance of Being Inconsistent

The noble gas dimers as a probe of the energetic contributions of dispersion and short-range electron correlation in weakly bound systems

Contact Info

Product

Resources

About