Diffusion in CLES

Sylvie Theado

Abstract. The most advanced version of CLES (Code Liégeois d'Evolution Stellaire) can compute the abundance variations due to microscopic diffusion for a dozen species. The diffusion velocities are computed following the theory developped by Thoul et al. (1994). In this talk I will rapidly remind the fundamental equations which govern the chemical evolution and the diffusion theory. I will present their implementation in CLES and the numerical technique used to compute the diffusion-induced abundance variations.