2Donetsk A.A. Galkin Physics and Technology Institute of the National Academy of Sciences of Ukraine 72 R. Luxemburg Str., Donetsk 83114, Ukraine
Received September 24, 2012
A model with deformed atom shells is built to investigate the elastic properties of rare-gas crystals Ne and Kr under high pressure. It is shown that the observed deviation from the Cauchy relation δ cannot be adequately reproduced with taking into account of only the many-body interaction. The individual pressure dependence δ of is
a result of competition of the many-body interaction and the quadrupole interaction associated with the quadrupole-type deformation of electron shells of the atoms during the displacements of the nuclei. Each kind of interaction makes a strongly pressure dependent contribution to δ . In the case of Ne and Kr, contributions of these interactions are compensated to the good precision, providing δ being almost constant against pressure.
PACS: 62.50.–p High-pressure effects in solids and liquids; PACS: 62.65.+k Acoustical properties of solids; PACS: 64.10.+h General theory of equations of state and phase equilibria.