The formation energy and structural relaxation of a vacancy were calculated within the framework of the local density approximation and the ab initio pseudopotential method for super-cells. This corrected a small error in the pseudopotential which had been used in previous calculations. The calculated value of 0.54eV was almost identical to the activation energy for self-diffusion. This suggested an extraordinarily small vacancy migration energy or a non-vacancy mechanism of self-diffusion. The results for self-interstitials excluded an interstitialcy mechanism. A local relaxation volume of -0.51 atomic volumes was found for the vacancy.

Properties of Monovacancies and Self-Interstitials in BCC Li: an ab initio Pseudopotential Study. W.Frank, U.Breier, C.Elsässer, M.Fähnle: Physical Review B, 1993, 48[10], 7676-8