The Density Domain Approach to Chemical Bonding DDA

The chemical bonds of a molecule are usually imagined as lines interconnecting the nuclei. The formal bond system of these lines may be thought of as the molecular skeleton. However, this bond skeleton does not fully rep- 

One may follow the shape changes of the contour surface G(a) as the parameter value a scans the interval (0, ). Essential changes, such as connections between parts of G a)y occur only at a small, finite number of selected contour values Ui. The various parts of G a) and the pattern of their connections, as a function of the parameter a, provide a new, systematic approach to chemical bonding. 

Fi e 3 Two approximate isodensity surfaces of the butadiene molecule, obtained for density contour parameter values a = 0.25c/(a.u.) and a = 0.02c/(a.u.), respectively. Note that according to the density domain approach (DDA) to chemical bonding, all molecular fragments are bonded together at both density levels shown. 

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