Ernst Schumacher, University of Bern
Prof.em of Chemistry, Dep. Chemistry and Biochemistry
This site presents a quantitative Lewis model of molecular structure, using G.E. Kimball's free [spherical electron probability] clouds
Note: Drawings of "electron clouds" or "orbitals" on a molecular skeleton in any approximation represent helpful visualizations, not the "truth"! The same holds for the not existing "bonding sticks" and the arbitrary cores.
Gallery of examples

Orbital surfaces are the set of points at a selected amplitude of the spatial wavefunction φ, which is unlimited. Computed by Gaussian03™, drawn by WebMO™. Cores are arbitrary. ⟨φφ⟩ would show density surfaces (like those at right) of similar shape.

Kimball's free electron probability clouds are simple computational tools, explained in these pages. Their surface is the set of points at the expected radius ⟨φrφ⟩ of an unlimited stype density distribution for every sphere (Tutorials). [He] cores are computed, too. Program from ES with Mathematica™.

Both charge distributions give nearly the same Vee, Vne. 
