Electric quadrupole interactions and the - phase transition in Ce: the role of conduction electrons

Николаев, А. В.; Michel, K. H.

doi:10.1007/s100510070156

Cited by 18 publications

(62 citation statements)

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“…However, there is another approach [73][74][75] which treats the phase change as a hidden structural transformation (see Sec. 6).…”

Section: Figurementioning

confidence: 99%

“…[73][74][75]37] a distinctive approach is presented, which considers the  phase transition as a hidden structural transformation. Note that its intrinsic feature is softening of bulk modulus and elastic anomalies [69,78,80] (Sec.…”

Section:  Transformation As a Hidden Structural Phase Transitionmentioning

confidence: 99%

“…[74,75,37] the  phase transition is considered to be structural, albeit with a very special space symmetry lowering. The main peculiarity is that the suggested symmetry change concerns the electron density but conserves the fcc lattice of cerium nuclei in the -phase.…”

Section: Quadrupolar Model Of the  Transitionmentioning

confidence: 99%

“…[74] the intersite Coulomb interaction between f-electrons was considered, in Ref. [75] the intersite Coulomb repulsion of s-, d-, felectron densities were introduced and in Ref. [37] two electron (f-and d-) intrasite and intersite repulsions were accounted for.…”

Section: Quadrupolar Model Of the  Transitionmentioning

confidence: 99%

“…The idea on the nonisomorphic nature of the  transition was independently formulated in Refs. [74,75,37], where a quadrupolar ordering of the electron density in the -phase was considered as the driving force for the phase transformation. Although the quadrupolar model can be viewed as a continuation of the approach of Eliashberg and Capellmann, already in the first work [74] it was claimed that there is no distortions of the fcc lattice of cerium nuclei, and all structural changes are associated with electronic density of the valence electrons.…”

Section: Thermodynamic Analysis Of Eliashberg and Capellmannmentioning

confidence: 99%

See 4 more Smart Citations

The puzzle of the $ \gamma\to\alpha$ and other phase transitions in cerium

Николаев¹,

Tsvyashchenko²

2012

Phys.-Usp.

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“…However, there is another approach [73][74][75] which treats the phase change as a hidden structural transformation (see Sec. 6).…”

Section: Figurementioning

confidence: 99%

Section:  Transformation As a Hidden Structural Phase Transitionmentioning

confidence: 99%

Section: Quadrupolar Model Of the  Transitionmentioning

confidence: 99%

Section: Quadrupolar Model Of the  Transitionmentioning

confidence: 99%

Section: Thermodynamic Analysis Of Eliashberg and Capellmannmentioning

confidence: 99%

See 3 more Smart Citations

The puzzle of the $ \gamma\to\alpha$ and other phase transitions in cerium

Николаев¹,

Tsvyashchenko²

2012

Phys.-Usp.

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Solution of periodic Poisson's equation and the Hartree–Fock approach for solids with extended electron states: Application to linear augmented plane wave method

Николаев

D’yachkov

2002

Int J of Quantum Chemistry

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ABSTRACT:We formulate a Hartree-Fock-LAPW method for electronic band structure calculations. The method is based on the Hartree-Fock-Roothaan approach for solids with extended electron states and closed core shells where the basis functions of itinerant electrons are linear augmented plane waves. All interactions within the restricted Hartree-Fock approach are analyzed and in principle can be taken into account. In particular, we obtained the matrix elements for the exchange interactions of extended states and the crystal electric field effects. To calculate the matrix elements of exchange for extended states, we first introduce an auxiliary potential and then integrate it with an effective charge density corresponding to the electron exchange transition under consideration. The problem of finding the auxiliary potential is solved by using the strategy of the full potential LAPW approach, which is based on the general solution of periodic Poisson's equation. Here, we use an original technique for the general solution of periodic Poisson's equation and multipole expansions of electron densities. We apply the technique to obtain periodic potentials of the face-centered cubic lattice and discuss its accuracy and convergence in comparison with other methods.

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Crystal structures of polymerized fullerides AC60, A=K, Rb, Cs, and alkali-mediated interactions

Verberck

Michel

Николаев

2002

The Journal of Chemical Physics

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Intercalation of heavy alkali metals (K, Rb and Cs) in the bundles of single wall nanotubes AIP Conf.Starting from a model of rigid interacting C 60 polymer chains on an orthorhombic lattice, we study the mutual orientation of the chains and the stability of the crystalline structures Pmnn and I2/m. We take into account ͑i͒ van der Waals interactions and electric quadrupole interactions between C 60 monomers on different chains as well as ͑ii͒ interactions of the monomers with the surrounding alkali atoms. The direct interactions ͑i͒ always lead to an antiferrorotational structure Pmnn with alternate orientation of the C 60 chains in planes ͑001͒. The interactions ͑ii͒ with the alkalis consist of two parts: translation-rotation ͑TR͒ coupling where the orientations of the chains interact with displacements of the alkalis, and quadrupolar electronic polarizability ͑ep͒ coupling, where the electric quadrupoles on the C 60 monomers interact with induced quadrupoles due to excited electronic d-states of the alkalis. Both interactions ͑ii͒ lead to an effective orientation-orientation interaction between the C 60 chains and always favor the ferrorotational structure I2/m, where C 60 chains have a same orientation. The structures Pmnn for KC 60 and I2/m for Rb-and CsC 60 are the result of a competition between the direct interaction ͑i͒ and the alkali-mediated interactions ͑ii͒. In Rb-and CsC 60 the latter are found to be dominant, the preponderant role being played by the quadrupolar electronic polarizability of the alkali ions.

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Electric quadrupole interactions and the - phase transition in Ce: the role of conduction electrons

Cited by 18 publications

References 1 publication

The puzzle of the $ \gamma\to\alpha$ and other phase transitions in cerium

The puzzle of the $ \gamma\to\alpha$ and other phase transitions in cerium

Solution of periodic Poisson's equation and the Hartree–Fock approach for solids with extended electron states: Application to linear augmented plane wave method

Crystal structures of polymerized fullerides AC60, A=K, Rb, Cs, and alkali-mediated interactions

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