The formation and binding energies of divacancies in the body-centered cubic metal were calculated by using ab initio electron theory and a super-cell approach. The results showed that the activation energy for self-diffusion via divacancies should be much higher than that for self-diffusion via monovacancies. This conflicted with analyses of experimental self-diffusion data derived from nuclear magnetic resonance relaxation rates, in terms of a combined monovacancy-divacancy mechanism, which yielded similar activation energies for monovacancies and divacancies. It was concluded that a contribution which arose from divacancies could not explain the observed curvature of the Arrhenius plot for Li self-diffusion at high temperatures.

Theory of Self-Diffusion in Alkali Metals - the Influence of Divacancies in Li. V.Schott, M.Fähnle, P.A.Madden: Journal of Physics - Condensed Matter, 2000, 12[7], 1195-8