Elementary Quantum Chemistry of the Surface Chemical Bond

5 Elementary Quantum Chemistry of the Surface Chemical Bond 

The interaction of an adatom with transition-metal surface atoms results in the broadening and shifting of the atomic orbital energies. There is not only a change in the electron distribution on the adatom, but also in the metal atoms involved in the sin-face chemical bond. Upon formation of the adsorbate surface chemical bond, the interaction between the surface atoms weakens. 

In a very elementary fashion, this can be described with Bond Order Conservation theoryl l. This approximate theory assnmes spherical electron densities aronnd each of the atoms, and hence ignores hybridization. It is based on Pauling s observation that bond lengths between atoms in complexes depend logaritmically on the bond order x of each bond  

If the two center interaction that comprises the chemical bond is described by a Morse potential then a simple relation follows between the potential Q x) and the bond order  

1) If an atom has n neighbors rather than one, the total bond strength can be written 

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