Elastic constants and electronic structure of fluorite (CaF2): an ab initio Hartree-Fock study

作者：M. Catti, Alessandrο Pavese, V. R. Saunders · 发表于：Journal of Physics Condensed Matter · 年份：1991 · DOI：10.1088/0953-8984/3/23/004 · 被引用次数：115 · 研究领域：Inorganic Fluorides and Related Compounds、Inorganic Chemistry and Materials、Heusler alloys: electronic and magnetic properties

The ground state properties of fluorite (CaF 2 ) have been studied using CRYSTAL, an ab initio periodic Hartree-Fock program. Twenty-two and thirteen atomic orbitals (represented as contracted Gaussian-type functions) are used for the calcium and fluorine atoms, respectively. The binding energy (BE), the equilibrium lattice parameter (a), the elastic constants (C ij ) and the central zone phonon frequencies nu (IR) and nu (Raman) have been evaluated, and a good agreement obtained with experiment (for instance the error is +2.0, +1.7, -0.5% for BE, a and C 11 , respectively). The calculated C 44 elastic constant reduces from 48 to 44 GPa (experimental value: 37 GPa) when the fluorine atoms are allowed to displace under strain, indicating the importance of inner deformation for shear elasticity. Electron density maps, density of states and band structure plots are reported which confirm the fully ionic nature of fluorite.