Electron density, exchange-correlation density, and bond characterization from the perspective of the valence-bond...

In this work we have analyzed the bond character of a series of representative diatomic molecules, using valence bond and the atoms in molecules points of view. This is done using generalized valence-bond calculations. We have also employed more exigent levels, as configuration interaction with single and double excitations and complete active space self-consistent field calculations, in order to validate the generalized valence-bond results. We have explored the possibility that the known delocalization index, and a parameter that measures the excess or defect population within a given atomic basin, can be considered as indicators of the character of bond interaction. We conclude that for a proper description of the bond character, the global behavior of both the charge and two-electron densities should be considered.