Abstract
The self-diffusion coefficients of b.c.c. metals are analysed assuming a two-defect model and different one-defect models. The two-exponential fits reveal large error limits for the diffusion parameters. Only for V, Nb and Na are highly accurate monovacancy diffusion energies evaluated. The analysis shows that for the refractory metals and for the alkaline metals the competition of two mechanisms is more probable than a strong temperature dependence of the monovacancy diffusion parameters.