Ion-charge resolved 3p photoabsorption measurements of atomic Cr

In this letter, high resolution, ion-charge resolved photoabsorption spectra of free ground state chromium atoms are presented. Using a time-of-flight spectrometer the ion yield of Cr1+ and Cr2+ in the 3p resonance region was recorded. These final-charge separated spectra reveal features that have not been seen before. The double ionization signal shows a stepwise increase at the 3p direct ionization threshold, resulting from spin-dependent decay channels into the final ionic states. Several resonances show different line shapes in both ionization channels; in particular a newly observed Rydberg series exhibits a reversal of its asymmetric Fano profiles. (letter to the editor)