been generally ignored. In order to determine whether EIMI can or cannot be neglected, we have studied iron charge-state abundances by incorporating EIMI cross sections into calculations for CIE, equilibration timescales, and time-dependent ionization.

We find that for CIE it is justified to ignore EIMI, as the influence is less than 5% for iron. EIMI has a more significant influence on the CSD of ionizing plasmas and can decrease the timescale at which changes in the CSD begin to occur by $\sim 10\%$ at temperatures around 10$^{7}$ K. However, currently the uncertainties in EISI cross sections are likely to be more important than whether EIMI is included or neglected.

The greatest change we found when including EIMI is for an oscillation in the temperature. In this scenario we found cases where the ion abundances may differ by up to 50% from what is predicted when EIMI is neglected. One context in which such temperature oscillations occur is nanoflare heating of the solar corona. Based on our results, nanoflare models should incorporate EIMI in order to accurately predict the spectrosopic signatures of nanoflares.

A challenge for incorporating EIMI into plasma models is the lack of any reliable EIMI theory and the 