Ab initio theory of the many-body interaction and elastic properties of rare-gas crystals under pressure

The short‐range many‐body forces induced by the overlap of electron shells of atoms have been investigated. The nonorthogonality of atomic orbitals of the nearest‐neighbor atoms of a crystal leads to the appearance of terms in the potential energy, which depend on the coordinates of three, four, and...

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Bibliographic Details
Published in:Physica Status Solidi. B: Basic Solid State Physics 2014-04, Vol.251 (4), p.774-787
Main Authors: Varyukhin, V. N., Troitskaya, E. P., Chabanenko, Val. V., Gorbenko, Ie. Ie, Pilipenko, E. A.
Format: Article
Language:English
Subjects:
Approximation
Compressing
Crystals
Deviation
elastic properties
many-body interaction
Mathematical analysis
Nuclear power generation
Orbitals
pressure
rare-gas crystals
Shells
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Summary:The short‐range many‐body forces induced by the overlap of electron shells of atoms have been investigated. The nonorthogonality of atomic orbitals of the nearest‐neighbor atoms of a crystal leads to the appearance of terms in the potential energy, which depend on the coordinates of three, four, and more nearest‐neighbor atoms. An expression has been obtained for the energy of the electron subsystem of the crystal in the Hartree–Fock approximation in the basis set of atomic orbitals exactly orthogonalized at different crystal sites. The behavior of the contributions from two‐body and three‐body interactions to the crystal energy under compression has been analyzed. The short‐range three‐body potential has been calculated from first principles and proposed in the simple form. The three‐body forces, obtained change the behavior of the dispersion curves for all wave vectors, in particular, thus violating the Cauchy relation. The theoretical and experimental deviations from the Cauchy relation for Ne and Ar are in good agreement under pressure.
ISSN:0370-1972
1521-3951
DOI:10.1002/pssb.201350065