An ab initio study of the fcc and hcp structures of helium
- 14 May 2006
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 124 (18), 184502
- https://doi.org/10.1063/1.2192501
Abstract
The hexagonal close packed (hcp) and face centered cubic (fcc) structures of helium are studied by using a new ab initiocomputational model for large complexes comprising small subsystems. The new model is formulated within the framework of the energy incremental scheme. In the calculation of intra- and intersystem energies, model systems are introduced. To each subsystem associated is a set of partner subsystems defined by a vicinity criterion. In the independent calculations of intra- and intersystem energies, the calculations are performed on model subsystems defined by the subsystems considered and their partner subsystems. A small and a large basis set are associated with each subsystem. For partner subsystems in a model system, the small basis set is adopted. By introducing a particular decomposition scheme, the intermolecular potential is written as a sum of effective one-body potentials. The binding energy per atom in an infinite crystal of atoms is the negative value of this one-body potential. The one- body potentials for hcp and fcc structures are calculated for the following nearest neighbor distances ( d 0 ) : 4.6, 5.1, 5.4, 5.435, 5.5, 5.61, and 6.1 a.u. The equilibrium distance is 5.44 a.u. for both structures. The equilibrium dimer distance is 5.61 a.u. For the larger distances, i.e., d 0 > 5.4 a.u. , the difference of the effective one-body potentials for the two structures is less than 0.2 μ E h . However, the hcp structure has the lowest effective one-body potential for all the distances considered. For the smallest distance the difference in the effective one-body potential is 3.9 μ E h . Hence, for solid helium, i.e., helium under high pressure, the hcp structure is the preferred one. The error in the calculated effective one-body potential for the distance d 0 = 5.61 a.u. is of the order of 1 μ E h ( ≈ 0.5 % ) .Keywords
This publication has 30 references indexed in Scilit:
- Interatomic potential for the X1Σ state of Be2, revisitedInternational Journal of Quantum Chemistry, 2004
- State of the Art and Challenges of the ab Initio Theory of Intermolecular InteractionsChemical Reviews, 2000
- Ab initiocalculation of ground-state properties of rare-gas crystalsPhysical Review B, 1999
- Closed-shell interaction in silver and gold chloridesThe Journal of Chemical Physics, 1998
- An incremental approach for correlation contributions to the structural and cohesive properties of polymers. Coupled-cluster study of trans-polyacetyleneChemical Physics, 1997
- Cohesive energies of cubic III-V semiconductorsPhysical Review B, 1996
- Correlation effects in ionic crystals: The cohesive energy of MgOPhysical Review B, 1995
- Correlation energy of diamondPhysical Review B, 1992
- The correlation energy of crystalline siliconChemical Physics Letters, 1992
- Derivation of an extended geminal modelThe Journal of Chemical Physics, 1983