Topological analysis charge densities

Most of the relevant features of the charge density distribution can be elegantly elucidated by means of the topological analysis of the total electron density [43] nevertheless, electron density deformation maps are still a very effective tool in charge density studies. This is especially true for all densities that are not specified via a multipole model and whose topological analysis has to be performed from numerical values on a grid. 

Initially, the topological approach has been widely used only for the analysis of theoretical charge densities. Theoretical analysis allows us to consider two atoms as bonded, whereas experiments show only their spatial proximity (x-ray or neutron diffraction), changes in the vibrational behavior of an H-X bond involved in interaction, changes in magnetic shielding of target nuclei (NMR), and so on. 

Space Partitioning and Topological Analysis of the Total Charge Density... 

The study of the nature of the Si—O bond through analysis of its charge density is based on net ionic charges, heights of peaks in atom deformation density maps, and, more recently, topological analysis of the total charge density. 

With the topological analysis of the total charge density, the distinction between a covalent and a closed-shell ionic interaction can be based on the value of the Laplacian and its components at the bond critical point. Such an analysis will be most conclusive when done on a series of related compounds, analyzed with identical basis sets, as the topological values of the model density from experimental data have been found to be quite dependent on the choice of basis functions. 

Small cyclic delocalization according to the topological analysis of charge density. 

An analysis of the topological characteristics of electron density was performed for the studied Sarin-magnesium oxide complexes following Bader s Atoms in Molecules Theory (AIM).82 This analysis can be used to characterize hydrogen bonding solely from the charge density. There have been formulated several effects... 

Once the multipole analysis of the X-ray data is done, it provides an analytical description of the electron density that can be used to calculate electrostatic properties (static model density, topology of the density, dipole moments, electrostatic potential, net charges, d orbital populations, etc.). It also allows the calculation of accurate structure factors phases which enables the calculation of experimental dynamic deformation density maps [16] ... 

Another promising application of charge density studies is the topological analysis of p(r), possibly also of V(r). 

Several alternatives to the Mulliken population have been presented that attempt to provide more rigorous estimates of the charges on atoms in molecules or clusters although not all have been applied in chemisorption and catalysis. We quote the Natural Bond Order analysis, and the elegant topological analysis of the electron density or of the electron localization function, ELF, introduced by Becke and Edgecombe. " ELF analysis has... 

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