ATOMDB
26 0.0000
FeXVIII
Iron
[Ar]³d⁶4s²

This is some front matter.

Level 1 → 2
Electron configuration 3d⁶ 4s¹ → 3d⁶ 4s¹
Energy above ground 0.0000 → 0.0477
Quantum state
n L degeneracy parity
4 2 → 2 10 → 8 even → even
Energy level data source 2009A&A...498..915D
Photoionization data source 1995A&AS..109..125V

And this here would be some stuff for after the table