Electronic and structural properties of CaH2:: an ab initio Hartree-Fock study

The Hartree-Fock ab initio method has been used to evaluate some structural and electronic properties of the CaH2 crystal. The calculated quantities include the crystalline parameters, binding energy, elastic constants, band structure, density of states and electronic charge distribution. Taking into account the correlation effects, the experimental binding energy is well reproduced. The band energies, density of states and charge density maps are analyzed, and the nature of chemical bonding is discussed, showing significant deviations from ionicity (z(ca) = 1.867\e\). The values of elastic constants C-11, C-12, C-13, C-22, C-23, C-33, C-44, C-55, C-66 and bulk modulus, determined for the first time, are 14.4, 110.3, 67.9, 75.1, 143.1, 36.6, 111.1, 68.7, 81.6 and 202.8 GPa, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.