Van der Waals Repulsion
Overlap of electron clouds
Theory provides little guidance on form of model
Two popular treatments
inverse power exponential
typically n ~ 9 - 12 two parameters
Combine with attraction term
- Lennard-Jones model Exp-6
a.k.a. “Buckingham” or “Hill”
Exp-6 repulsion is slightly softer
Beware of anomalous Exp-6 short-range attraction