An apparent inability of density functional theory to describe vacancies accurately and consistently, within the local density and generalized gradient approximations, was pointed out and resolved. The apparent difficulty was traced to electron correlation effects near to electronic edges, and it was shown how corrections could be made for these. It was found that the divacancy in Al was energetically unstable, and that anharmonic atomic vibrations explained the non-Arrhenius temperature dependence of the vacancy concentration.

Vacancies in Metals - from First-Principles Calculations to Experimental Data. K.Carling, G.Wahnström, T.R.Mattsson, A.E.Mattsson, N.Sandberg, G.Grimvall: Physical Review Letters, 2000, 85[18], 3862-5