The Perdew-Burke-Enzerhof functional, and the generalized gradient approximation, is a Big Honking Deal for accurate quantum-mechanical simulation of solids. F

The Perdew-Burke-Enzerhof functional, and the generalized gradient approximation, is a Big Honking Deal for accurate quantum-mechanical simulation of solids. For more: http://en.wikipedia.org/wiki/Density_functional_theory http://en.wikipedia.org/wiki/Density_functional_theory (I used to be a happy customer, back when I was a scientist.)