Fe ii column densities for the fine structure levels of the ground state (black filled circles) and of the first excited level (red open squares) for component I in the spectrum of GRB 120327A. Column density predictions from our time-dependent photo-excitation code are also shown. They refer to the fine structure levels of the ground state (solid black lines) and to the fine structure levels of the first excited level (red dashed lines), in the case of an absorber placed at 200 pc from the GRB. The arrow represents the 90% upper limit to the column density of the first fine structure level of the ground state, computed using the second-epoch spectrum. For clarity reasons, black points and curves have been slightly offset to the right.