Electron-impact excitation data for astrophysical plasma models

Plasma models built on extensive atomic data are essential to interpret the observed X-ray spectra. The derived physical properties of astrophysical plasmas using different plasma codes do not necessarily agree, especially in the context of high-quality spectra obtained with future missions like XRISM, Athena/X-IFU, Arcus, and HUBS. Electron-impact excitation is one of the fundamental atomic processes in astrophysical plasmas. In this talk, I will describe recent R-matrix calculations of electron-impact excitation data for C-, N-, and O-like cosmic abundant ions. I will also discuss what is still needed to improve the completeness and accuracy of atomic databases widely used in the community