Ab initio periodic Hartree-Fock study of lizardite 1T

A periodic ab initio Hartree-Fock LCAO study was performed on the 1:1 sheet silicate lizardite, Mg₃Si₂O₅(OH)₄, which has P31 m symmetry. A total of 258 atomic orbitals were described using double-zeta-quality basis sets augmented with polarization d (Si, Mg, O) and p (H) functions. Density of states and electron charge-density maps were calculated to investigate the electronic properties. The majority of the valence states are composed of O and Si atomic orbitals with little contribution from H atoms. Calculations showed that although there are about 0.5|e| in Si d and about 0.1 |e| in Mg d orbitals, the population of O d orbitals is negligible. The maps of charge density show that interlayer hydrogen bonds fix adjacent 1:1 layers. Positions of the main O peaks in projected density of states evaluated for both three-dimensional (3D) and two-dimensional (2D) calculations were influenced by layer-to-layer interactions, especially hydrogen bonds.