Investigation of the Structures and Chemical Bonding of Mn2Ge6– and Mn2Ge7– Clusters via Anion Photoelectron Spectroscopy and Theoretical Calculations

We present joint anion photoelectron spectroscopy and theoretical studies for Mn₂Ge₆^- and Mn₂Ge₇^-. Experimental results show that Mn₂Ge₆^- and Mn₂Ge₇^- have vertical electron detachment energies of 2.58 ± 0.08 and 2.88 ± 0.08 eV, respectively. Both Mn₂Ge₆^- and Mn₂Ge₆ have C_s symmetric structures with a Mn atom attached to a pentagonal bipyramid MnGe₆. Both Mn₂Ge₇^- and Mn₂Ge₇ have C_2v symmetric structures, which can be considered as two Mn₂Ge₄ tetragonal bipyramids sharing a MnGeMn face. According to chemical bonding analyses, Mn₂Ge₆ could be considered as a (Mn^II)(MnGe₆^2-) complex. Theoretical calculations predict that the extension of Mn₂Ge₇ to Mn_2nGe_4n+3 may be able to produce a new type of Mn-doped germanium nanostructure.