title: Four-body interaction energy for compressed solid krypton from quantum theory.
abstract: The importance of the four-body contribution in compressed solid krypton was first evaluated using the many-body expansion method and the coupled cluster theory with full single and double excitations plus perturbative treatment of triples. All different four-atom clusters existing in the first- and second-nearest neighbor shells of face-centered cubic krypton were considered, and both self-consistent-field Hartree-Fock and correlation parts of the four-body interaction were accurately determined from the ambient conditions up to eightfold volume compression. We find that the four-body interaction energy is negative at compression ratio lower than 2, where the dispersive forces play a dominant role. With increasing the compression, the four-body contribution becomes repulsive and significantly cancels the over-softening effects of the three-body potential. The obtained equation of state (EOS) was compared with the experiments and the density-functional theory calculations. It shows that combination of the four-body effects with two- and three-body interactions leads to an excellent agreement with EOS measurements throughout the whole experimental range 0-130 GPa, and extends the prediction to 300 GPa.
authors.affiliation: Department of Physics, Southwest University, Chongqing 400715, China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Tian
authors.forename: Na
authors.initials: N
authors.lastname: Wu
authors.forename: Fusheng
authors.initials: F
authors.lastname: Liu
authors.forename: Surendra K
authors.initials: SK
authors.lastname: Saxena
authors.forename: Xingrong
authors.initials: X
authors.lastname: Zheng