Diffusion processes in a liquid mixture of lithium isotopes

Abstract

The quantum mechanical theory of diffusion, as recently developed for liquid metals [M. Omini, Phil. Mag. 86 1643 (2006); Phil. Mag. 87 5249 (2007)], is now presented in a final version that improves and clarifies the original formulation. The new formulation uses a convergent variational method to solve the transport equation and confirms, through a rigorous analysis, the validity of the approximations introduced in the quoted papers. As a consequence, all previous calculations, concerning the self diffusion coefficients of liquid lithium isotopes, are automatically confirmed. The possibility of obtaining, as a limit of a convergent procedure, the true solution of the transport equation allows a reliable prediction of all isotope effects. In particular, it provides numerical values for the interdiffusion coefficients of 6Li and 7Li, which were not explicitly deduced in the previous works. The total consistency of these values with those measured by Feinauer et al. [Phys. Condens. Matter 6 L355 (1994)] further supports the theory. It is concluded that the whole set of experimental data on liquid lithium, as provided by the above authors, is theoretically explained within the experimental uncertainties.