Observation of a 'Giant Resonance' in the 3p Absorption Spectrum of Mn I

The absorption spectrum of Mn I in the energy region corresponding to excitation of the 3p-subshell (40-70 eV) has been recorded for the first time. At least 10 discrete features are reported, as well as a broad modulation in the continuous absorption immediately above the 3p-thresholds. The spectrum is discussed in relation to previous photoabsorption data for nearby elements in the periodic table, and assignments are made by comparison with Hartree -Fock model calculations. The spectrum is dominated by a 3p-3d ‘giant resonance’.