Radiative accelerations and atomic data requirements

Radiative accelerations are crucial quantities to study element diffusion in stars. They strongly depend on atomic properties of ions in a way more or less similar to opacities or synthetic spectra. Computations of radiative accelerations however have also some specific requirements which make them very sensitive to the quality of atomic data. We shall present various aspects of the radiative accelerations computations and discuss, through examples, how they are so closely related to the knowledge of atomic data