Structural Phase Transformamtion and the Equation of State of CsCI, CsBr, and CsI Crystals

Narain, Jagdish; Dwivedi, Nidhi; Agrawal, G. G.; Shanker, J.

doi:10.1002/pssb.2221320208

Cited by 8 publications

(2 citation statements)

References 23 publications

(4 reference statements)

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“…The value of interatomic separation and CI as a function of T are reported in Tables 4 and 5. Among all the alkali halides CsCl is the only crystal which is transformed from CsC1-type structure to NaC1-type structure under the effect of high temperature at 742 K [19]. Therefore, in the present paper we have investigated CsCl only up to 742 K though its melting temperature is 919 K. Srivastava and Merchant (SM) [15] have also investigated the thermal expansion through the equation of state by measuring the lattice parameters for CsC1, CsBr, and CsI from room temperature to the melting temperature using the X-ray diffraction technique.…”

Section: Resultsmentioning

confidence: 99%

Thermal Expansion and Compression of Alkaline Earth Oxides and Cesium Halides at High Temperature and High Pressure

Upadhyay

Kumar

1995

Physica Status Solidi (b)

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Temperature and pressure dependence of thermal expansion and compression of alkaline earth oxides and cesium halides with NaCI-and CsC1-type structures is investigated. The theory of interionic potentials based on the quantum mechanical form of the overlap repulsive energy is used to investigate the interatomic separations as a function of temperature and pressure from room temperature up to the melting temperature and from zero pressure up to the structural transition pressure. The values of van der Waals dipole--dipole and dipole-quadrupole energies are also included in the model. The results are used to predict the temperature and pressure dependence of the coefficient of volume thermal expansion using a formula derived on the basis of the thermodynamic analysis. The results are compared with available experimental data and discussed in the light of recent research.

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Section: Resultsmentioning

confidence: 99%

Thermal Expansion and Compression of Alkaline Earth Oxides and Cesium Halides at High Temperature and High Pressure

Upadhyay

Kumar

1995

Physica Status Solidi (b)

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“…[7][8][9][10][11][12][13][14] Many of these studies have employed approximate methods, rather than a full quantum mechanical treatment. For example, the self-consistent atomic deformation method 8 has been employed to compute the relative energy of these two structures for the alkali-metal halides.…”

Section: Introductionmentioning

confidence: 99%

Importance of dispersion in density functional calculations of cesium chloride and its related halides

et al. 2013

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The ionic compound cesium chloride adopts a cubic crystal structure bearing the same name. However, ab initio electronic structure calculations based on density functional theory methods using generalized gradient approximation functionals do not predict that cesium chloride adopts this phase. In this paper we apply semiempirical methods (density functional theory plus a pairwise dispersion correction) to account for missing van der Waals interactions within cesium chloride. The C 6 and R 0 dispersion parameters for cesium are established within Grimme's DFT + D2 formalism. Inclusion of the dispersion corrections is found not only to improve the quality of structures in comparison to experiment for all cesium halides, but also leads to the correct prediction of the ground-state phase under ambient conditions.

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Analysis of the Structural Phase Transition in Mixed Alkali Halide Crystals

Shanker

Sharma

Kumar

1987

Physica Status Solidi (b)

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An analysis of structural transition in CsCl-KCl and CsCI-RbCl mixed crystals is presented by studying the lattice stability in terms of interionic potentials. The potential parameters are determined by fitting the experimental values of lattice energies in standard observed structure viz. CsCl structure for CsCl and CsBr crystals, and NaCl structure for RbCl and KC1 crystals. It is found that CsCl-KCl mixed crystals remain stable in CsCl structure only for KCl less than 25%, and are transformed to NaCl structure when the proportion of KC1 becomes equal to or more than 25%. For CsCI-RbC1 mixed crystals, the transition from CsCl to NaC1 structure is predicted when the RbCl component becomes equal to or more than 50%. These predictions are found to be in good agreement with experimental results. The lattice theory of structural stability is also applied to predict the transition temperatures for the mixed crystals viz. CsC1-KCI, CsCl-RbCl and CsC1-CsBr at which they transform from CsCl to KaC1 structure.Es wird eine Analyse der Strukturiibergange in CsCI-KCl-und CsC1-RbC1-Mischkristallen durch die Untersuchung der Gitterstabilitat mittels Interionenpotentiale durchgefuhrt. Die Potentialparameter werden durch Anpassung der experimentellen Werte der Gitterenergien in beobachteten Standardstrukturen z. B. CsC1-Struktur fur CsCl-und CsBr-Kristalle und NaC1-Struktur fur RbC1-und KCI-Kristalle bestimmt. Es wird gefunden, daS die CsCl-KCI-Mischkristalle in der CsCIStruktur nur fur einen KC1-Anteil kleiner als 25% stabil bleiben und in die NaC1-Struktur ubergehen, wenn der KCl-Anteil gleich oder groSer als 25% wird. Fur CsCI-RbCI-Mischkristalle wird ein ubergang von der CsCl zur NaC1-Struktur vorhergesagt, wenn der Anteil der RbC1-Komponente gleich oder groSer als 50% wird. Es wird gefunden, daS diese Vorhersagen in guter Ubereinstimmung mit den experimentellen Ergebnissen sind. Die Gittertheorie der Strukturstabilitat wird auch benutzt, um fur die Mischkristalle z. B. CsC1-KCI, CsCl-RbCI und CsC1-CsBr die ubergangstemperatnren, bei denen sie von der CsCl-zur NaCl -Struktur iibergchen, vorhersagen.

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Structural Phase Transformamtion and the Equation of State of CsCI, CsBr, and CsI Crystals

Cited by 8 publications

References 23 publications

Thermal Expansion and Compression of Alkaline Earth Oxides and Cesium Halides at High Temperature and High Pressure

Thermal Expansion and Compression of Alkaline Earth Oxides and Cesium Halides at High Temperature and High Pressure

Importance of dispersion in density functional calculations of cesium chloride and its related halides

Analysis of the Structural Phase Transition in Mixed Alkali Halide Crystals

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