Multicentre Bond Indices from the Generalized Population Analysis of Higher Order Densities

Based on the generalized population analysis of appropriate functionals derived from higher order densities, the multicentre bond indices were introduced at both SCF and post-SCF levels. The corresponding indices were applied to the visualization of bonding in several simple molecules both without and with three-centre bonds. The ability of the se indices to detect and to localize the presence of three-centre bonds was tested on the analysis of bonding in several simple boranes B2H6, B4HlO, B5H9\u27 The three centre bonds were always detected in complete agreement with expectations. The approach is quite general and can be applied to the visulization of bonding in other cases of molecules with complex bonding patterns