Four-body interaction energy for compressed solid krypton from quantum theory

• Published in: The Journal of chemical physics Vol. 137; no. 4; p. 044108
• Main Authors: Tian, Chunling, Wu, Na, Liu, Fusheng, Saxena, Surendra K, Zheng, Xingrong
• Format: Journal Article
• Language: English
• Published: United States 28.07.2012
• ISSN: 1089-7690
• DOI: 10.1063/1.4737183

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.