Many-body interaction and equation of state for solid krypton from ab initio calculation

Abstract

Using the many-body expansion method and the double cluster with full single and double excitations plus perturbative treatment of triples [CCSD(T)] and augmented correlation consistent quadruple zeta (aug-cc-pVQZ) basis set, many-body contributions to the cohesive energy and equation of state of face-centered cubic solid krypton were accurately calculated with the atomic distance R from 2·1 to 4·0 Å at the room temperature (T = 300 K) in the experimentally studied range of pressures (0–60 GPa). The results showed that many-body expansion potential of face-centered cubic solid krypton was an exchange convergent series, and the even many-body contributions to the cohesive energy were repulsive, whereas the odd many-body contributions to the cohesive energy were attractive. For the same atomic distance R, many-body potential energy would reduce when the many-body number increases. When the atomic distance R>3·4 Å, the interaction energy may be well-described by two-body potential energy. In the range of 2·4–3·4 Å, it needs to consider three-body potential energy. Below 2·4 Å, the four-body potential energy should be considered. Finally, it was studied that the isothermal compression properties of solid krypton at the pressure regions P < 60 GPa. The research results showed that the calculated and experimental results have a good consistency at the pressure ranges 0–60 GPa, and may be helpful to accurately explain the phenomenon of the experiment above 60 Gpa when the effects of four-body, five-body potential pressure are considered.