Momentum transfered to atoms through photoexcitation and photoionization causes diffusion which can create abundance anomalies in stars. Precise radiative accelerations are imperative in stellar evolutionnary codes since diffusion of the chemical elements can affect the evolution of stars. Improved atomic databases (e.g. the OPACITY Project) recently made available have led to significant improvements to radiative acceleration calculations. Detailed calculations on all ions of iron will be presented. The iron abundance supported below the convection zone of A and F type stars by radiative pressure predicted with these results are consistent with recent observations, within the uncertainties brought by the neglect of the diffusion of other abundant elements such as He, C, N and O.

Physics in Canada, vol. 52, no. 3, p. 116 (1996)