Abstract:
The thermodynamic properties of a compressed Ne crystal are studied theoretically ab initio with the allowance for the many-body interaction in the deformable atom model. In the repulsion potential, in parallel to the three-body interaction related to the overlap of electron shells of atom, the deformation of electron shells of dipole-type atoms is taken into account in the pair and three-body approximations. The specific heat capacity and the Debye temperature are calculated over wide range of pressures and temperatures using a dynamic matrix on the base of nonempiric short-range repulsion potential and the integration over ten main-value points of the Chadi–Kohen method. The contributions of three-body forces related to the overlap of the electron shells of atoms and also a deformation of the electron shells are shown to increase the specific heat capacity of the compressed fcc-Ne gas even at a zero pressure. The calculated temperature dependences agree well with the available experimental data and the calculations of other researchers.
Keywords:rare-gas crystals, three-body interaction, deformation of electron shells, phonon frequencies, specific heat capacity, the Debye temperature, high pressure.
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