Analysis of Energetic Effects in Lithium Fluoride Crystals by Means of Ab-initio and MESQUAC-MO-SCF Calculations

摘要

Ab-initio and MESQUAC-MO-SCF (Mixed Electrostatic QUAntum Chemical) calculations on LiF structures with various geometries are presented. The LiF oligomers were studied with fixed geometries, corresponding to structures found in the crystal. For these oligomers bond distance optimization was carried out and the corresponding results for their stabilization energy were compared with experimental measurements and results from former calculations, which included geometry optimization. Values for the conversion energy between several geometries of these oligomers are also presented. The MESQUAC-MO-SCF method applied to the solid state gave results close to experimental data. Surface effects on a LiF model crystal (cube with 216atoms with interionic distance 2.01A) are also presented.