Van der Waals Potentials in Ionic Crystals

Shanker, J.; Agrawal, G. G.

doi:10.1002/pssb.2221230102

Cited by 46 publications

(36 citation statements)

References 87 publications

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“…Moreover, the exponential factors are different in different pair interactions, whereas in the Born-Mayer potential a common value of hardness parameters has been taken for the cation-anion, cation-cation, and anion-anion interactions. This is not justified for the reasons discussed by Shanker and Agrawal [11]. If one takes unequal values of hardness parameters for the crystal, then the number of parameters becomes too large to be determined from the input data for the lattice parameter and bulk modulus.…”

Section: Resultsmentioning

confidence: 99%

“…The second and third terms are van der Waals (vdW) dipole-dipole and dipole-quadrupole energies. The constants C and D are related to the dipole-dipole (c ij ) and dipole-quadrupole (d ij ) interaction coefficients as follows [11]:…”

Section: Theory and Methods Of Calculationmentioning

confidence: 99%

“…The subscripts + -, + + , --represent the cation-anion, cation-cation, anion-anion interactions, respectively. The values of c ij and d ij are obtained from the Kirkwood-Muller formulae given below [11]:…”

Section: Theory and Methods Of Calculationmentioning

confidence: 99%

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Pressure-Interatomic Separation-Temperature Relationship of Alkali Halides

Liu

2011

Acta Phys. Pol. A

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A new method for the determination of pressure-interatomic separation-temperature relationship is investigated and applied for some alkali halides. The method is developed by using the Mie-Gruneisen equation of state and the Anderson thermal pressure and an ionic model based on Harrison's treatment of overlap repulsive potential which takes into account the interactions up to second neighbors. It is found that the new method yields satisfactory results in agreement with the available experimental data.

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Section: Resultsmentioning

confidence: 99%

Section: Theory and Methods Of Calculationmentioning

confidence: 99%

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Pressure-Interatomic Separation-Temperature Relationship of Alkali Halides

Liu

2011

Acta Phys. Pol. A

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“…The second possible source of the disagreement is due to the above-mentioned assumption of proportionality between the repulsion parameter B and the first coordination number v. In fact, this parameter is proportional to the lattice sum S n = y]7 vij/k ~, where kij = Rij/R o (R o is the shortest interatomic distance), which is a function of n and usually somewhat greater than v (e.g. Shanker & Agrawal, 1984). Thus, for the NaC1 structure type v=6, but $6 =6.5952 and S 8 = 6.1457, for the CsCI and CaF 2 structure types v = 8, but S 6 = 8.7088 and S 8 = 8.1575, for the ZnS structure type v = 4, but S 6 = 4.3544 and S 8 = 4.0787 etc.…”

Section: Independence Of the Main Expressions Of The Bvm From The Bonmentioning

confidence: 99%

Semi-empirical groundwork of the bond-valence model

Urusov¹

1995

Acta Crystallogr Sect B

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The bond-valence model (BVM) which relates the length R of a bond to its bond valence s is a widely used empirical approach to the interpretation and prediction of atomic arrangements in crystals. However, a theoretical foundation of the BVM appears to be fairly inadequate so far. In this paper derivations of the main expressions of R(s) Independence of the BVM from bonding character is the result of such a treatment. Interrelations between both versions of the BVM are also analyzed. Much attention is given to the question of transferability of the single bondlength parameter and to the special role of bond-specific values of the softness parameter. The latter is proved to be a simple function of the ionization potentials of bonded atoms. In turn, this explains the strong linear correlations between the single bond lengths from cations to a pair of anions and the relation between single bond lengths and atom sizes (sum of the covalent radii). It is demonstrated that a correction related to electronegativity difference is involved in this consideration. In general, one might conclude that the BVM becomes soundly based from both the empirical and semi-empirical viewpoints.

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“…This is not consistent with the fact that in most of the ionic crystals anion-anion interactions are much stronger than the cation-cation interactions. On the other hand, the overlap repulsive potential form derived analyt- Another important point is regarding the van der Waals potentials which depend sensitively on the electronic polarizabilities of chalcogenide ions [7]. The polarizabilities of chalcogenide ions are significantly larger [8] than the corresponding values for halide ions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Crystal Binding and Structural Phase Transition in Alkaline‐Earth and Alkali Chalcogenides

Chaturvedi

Sharma

Paliwal

et al. 1989

Physica Status Solidi (b)

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An analysis of crystal binding and structural phase transition is presented using an analytical potential form for the overlap repulsive energy derived by Harrison from quantum mechanical considerations. The potential model is applied to calculate the cohesive energies, bulk modulus, and its pressure derivative for fifteen alkaline-earth chalcogenides and fourteen alkali chalcogenides. Calculated values of bulk modulus are found to exhibit empirical correlationship with unit cell volume. The problem of relative stability and structural phase transition is also investigated for alkaline-earth chalcogenides. Values of transition pressure are obtained and found to present good agreement with experimental data.Mit einer analytischen von Harrison aus quantenmechanischen Betrachtungen abgeleiteten Potentialform wird eine Analyse der Kristallbindung und der strukturellen Phaseniibergiinge durchgefuhrt. Das Potentialmodell wird zur Berechnung der Kohiisionsenergie, des Elastizitiitsmoduls und seinen Druckableitnngen von funfzehn Erdalkalichalkogeniden und vierzehn Alkalichalkogeniden benutzt. Es wird gefunden, da13 die berechneten Werte des Elastizitiitsmoduls eine empirische Korrelation mit dem Volumen der Einheitszelle aufweisen. Das Problem der relativen Stabilitiit und strukturellen Phasenubergiinge wird auch fur Erdalkalichalkogenide untersucht. Werte des Ubergangsdruckes werden erhalten und gefunden, da13 sie gut mit experimentellen Werten ubereinstimmen.

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Van der Waals Potentials in Ionic Crystals

Cited by 46 publications

References 87 publications

Pressure-Interatomic Separation-Temperature Relationship of Alkali Halides

Pressure-Interatomic Separation-Temperature Relationship of Alkali Halides

Semi-empirical groundwork of the bond-valence model

Analysis of Crystal Binding and Structural Phase Transition in Alkaline‐Earth and Alkali Chalcogenides

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