Bond metallicity of materials from real space charge density distributions

摘要

Within the framework of the theory of atoms in molecules, AIM, it was recently proposed that the metallicity of a bond could be determined from the properties of the electron density at the bond critical point using the ratio ξ_J(r_(bcp)) = ρ(r_(bcp))/Δ~2ρ(r_(bcp)). In this study we have mined results published using AIM and considered three different local measures of the bond metallicity: the original metallicity defi_nition ξ_J(r_(bcp) ), a dimensionless metallicity indicator, ξ_m(r_(bcp)), and the value of Bohm's quantum potential at the bond critical point. A global measure of metallicity, the planarity index f, has also been examined. We focus this study on a broad range of elements, ions and compounds of the form of the later is M_p X_q, where 1≤ p≤2 and 1≤ q≤ 4. A pressure induced non-metallic-metallic phase transitionbonds of the Ge_3N_4 for the β- andγ- crystals is observed. The various metallicity measures agree well with experimental observations and are observed to give qualitatively similar results.