Coupling Coefficients and Elastic Constants of Caesium Halides

Sharan, B.; Tiwari, Lokender

doi:10.1002/pssb.19640070105

Cited by 19 publications

(2 citation statements)

References 19 publications

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“…Denoting these elements by a superscript 3, we can write X 1 ' -- the difference depends only on the purely three-body component od the interaction. If we ignore the effect of the three-body potential, our expressions for the elastic constants agree with those of Sharan and Tiwari (7). The small differences in the Coulomb contributions are due to the different ways used in obt,aining them.…”

supporting

confidence: 72%

Contribution of the Three‐Body Overlap Forces to the Dynamical Matrix of Cesium Chloride

Lal

Verma

1970

Physica Status Solidi (b)

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Recently Verma and Singh (1) have described a simple method of deriving the contribution of the three-body overlap energy in ionic solids (Lundqvist (2)) to the dynamical matrix of crystals with the sodium chloride structure. The use of these matrix elements within the framework of the shell model has given excellent agreements with experimental dispersion curves for a number of alkali halides (Singh and Verma (3, 4): Singh (5)). It will, therefore, be of interest to study the effect of the three-body overlap forces on the lattice dynamics of those alkali halides which also crystallize in the cesium chloride structure.The cesium chloride lattice COnSi6tS of two simple cubic lattices interpenetrating to form a b. c. c. structure. Consequently the threcebody elements of the dynamical matrix involve lattice sums over b. c. c. and 6. c. points, which can be evaluated by the method prescribed by Born and Bradburn ( 6 ) . Denoting these elements by a superscript 3, we can write X 1 ' --and even

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confidence: 72%

Contribution of the Three‐Body Overlap Forces to the Dynamical Matrix of Cesium Chloride

Lal

Verma

1970

Physica Status Solidi (b)

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“…such that G and V are the Coulomb and three-body force matrices evaluated by Sharan & Tiwari (1964) and Lai & Verma (1970), respectively. Also, since the ionic charge (Ze) in r.s.m.…”

Section: (A) General Formulationmentioning

confidence: 99%

An extended three-body force shell model for the lattice-dynamics of ionic crystals

Singh

Gupta

1976

Proc. R. Soc. Lond. A

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An extended three-body force shell model (e. t. s. m.) for the dynamics of ionic crystals of cesium chloride structure has been developed by reformulating the original t. s. m. The dynamical matrix of the model consists of the long-range Coulomb and three-body interactions and short-range overlap repulsions effective up to the second-neighbours. The off-diagonal elements of this matrix along symmetry directions contain a completely new term having significant contribution for unequal shell charges. The long-wave aspects of e. t. s. m. have been explored to describe the elastic and dielectric behaviour of the crystals. The adequacy of e. t. s. m. to describe the lattice dynamics has been investigated by applying it to the case of thallous bromide (TIBr). The overall agreement between theoretical and experimental results seems to be encouraging and gives some confidence to regard it as an appropriate model for the dynamical description of ionic crystals.

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Phonon Spectrum and Specific Heat of Caesium Chloride

Tiwari

Sharan

1965

Physica Status Solidi (b)

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The phonon spectrum and specific heats of caesium chloride are determined by KELLERMANN'S method. For the purpose of this calculation the first Brillouin-zone is divided into lox lox 10 parts which on correct enumeration yields a total of GOO0 frequencies. The agreement between t h e theoretical and the experimental values of the specific heats is satisfactory.Das Phononenspektruni und die spezifische Warme von Caesiumchlorid wurden mit der Kellermannschen Methode untersucht. Fiir die Berechnung wurde der Phasenrauni der ersten Brillouinschen Zone in 10 x 10 x 10 Teile unterteilt, die bei richtiger Numerierung 6000 li'requenzen ergeben. Die Vhereinstimmung zwischen den theoretischen und experimentellen Werten der spezifischen Warmc ist befriedigend.

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Coupling Coefficients and Elastic Constants of Caesium Halides

Cited by 19 publications

References 19 publications

Contribution of the Three‐Body Overlap Forces to the Dynamical Matrix of Cesium Chloride

Contribution of the Three‐Body Overlap Forces to the Dynamical Matrix of Cesium Chloride

An extended three-body force shell model for the lattice-dynamics of ionic crystals

Phonon Spectrum and Specific Heat of Caesium Chloride

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