This article is cited in 5 papers

Lattice dynamics

Energy of phonons and zero-point vibrations in compressed rare-gas crystals

E. P. Troitskaya^a, E. A. Pilipenko^a, E. E. Gorbenko<sup>bc

a</sup> O O Galkin Donetsk Institute for Physics and Engineering, National Academy of Sciences of Ukraine
^b Lugansk Taras Shevchenko National University
^c Lugansk National Agrarian University, Lugansk, Ukraine

Abstract: A dynamic matrix of rare-gas crystals is constructed on the basis of a nonempirical short-range repulsion potential taking into account the three-body interaction and dipole-type deformation of the electron shells of atoms in the two- and three-body approximations in the model of deformable and polorizable atoms. Ab initio calculations of the phonon energy for compressed rare-gas crystals were performed at the two and ten mean-value points of the Chadi–Cohen method in a wide pressure range. It is shown that the contribution of three-body forces associated with the overlap of the electron shells of nearest-neighbor atoms in the phonon frequencies is small against the background of pair interaction, even at high pressure and most noticeable in Xe. The contribution of the deformation of the electron shells in the two- and three-body approximations is different for the different mean-value points and increases with increasing pressure. Comparison of the zero-point energy calculated by the Chadi–Cohen method for compressed crystals of the Ne–Xe series was performed with the available experiment at $p$ = 0 and the results of other authors.

Keywords: rare-gas crystals, three-body interaction, deformation of electron shells, phonon frequencies, zero-point energy, high pressure.

Received: 24.04.2019
Revised: 24.04.2019
Accepted: 26.04.2019

DOI: 10.21883/FTT.2019.10.48266.468

 English version: Physics of the Solid State, 2019, 61:10, 1846–1853

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