Simulation on the growth of NiCl₂ crystal

Based on the density function theory (DFT) calculation of crystal faces (003), (101), (104), (018) and (113) of NiCl₂ via CASTEP program, total energy, surface energy, band structures and density of states (DOS) were investigated. The crystal morphology of NiCl₂ and the growth habit of the surface of NiCl₂ were calculated by Bravais-Friedel Donnay-Harker (BFDH) rules. The results show that vacuum width of 0.6 nm and atom layer of 3 are reasonable to the surface energy calcution. The energy state of NiCl₂ is far more stable when face (003) is mainly unfold faces, while the energy state would be instable when faces (101), (104), (018) and (113) are the mainly unfolded. The electric structure results show that the front valence electron of face (003) is active correspondingly. That is there may be some activity points on this face. The larger energy band gap of it shows that the inner electrons are more stable. The band structures and DOS analysis show that the number of high energy band of (003) slab near the Fermi energy is less than that of other slabs, which proves the system is more stable no thermodynamics when (003) is mainly unfold. BFDH calculation on NiCl₂ predicts the unfold faces (003) and (101) successfully and indicates (003) is the most important face. Other results show that the growth habits of NiCl₂ cell and its surface slabs are different, NiCl₂ cell, (003), (101) and (113) slabs are inclined to form crystal with hexagonal plate and bulk shapes, (104) and (018) slabs are inclined to form crystal with rod shape.