Atomic data from the IRON project

A new R-matrix calculation of rate coefficients for electron collisional excitation of $\ion{Fe}{xiii}$ is presented and compared to recent calculations of comparable complexity. At temperatures at which Fe12+ is typically found in the solar corona, the present results, which use the intermediate coupling frame transformation method, show significant differences compared to some earlier work. We use a large configuration interaction calculation with extensive correlation to assess the accuracy of our and earlier workers' scattering targets