Atom Energy in Crystals: Gibbs Free Energy

[aaaa202]

Does atom at the surface of a crystal have more or less energy than those in the bulk? And how does this relate to their Gibbs free energy?

 

[Useful nucleus]

The notion of energy per atom in a solid is a bit ambiguous.
The surface atoms are under-coordinated (less number of bonds), thus it is expected that the average potential energy on the surface should be higher compared to the bulk.
I do not recall any general conclusion about the vibrational free energy of the surface or its stress-volume energy.

 

[bcrowell]

At atom at the surface has a higher electrical PE than an atom in the bulk. This is because the electric force on the atom is inward.

 

[aaaa202]

So is the surface energy simple the excess energy that the surface atoms have due to unsaturated Bonds?

 

[Useful nucleus]

So is the surface energy simple the excess energy that the surface atoms have due to unsaturated Bonds?

This is the "unrelaxed" surface energy.