Identification of Ge═O Double Bonds in Planar MnGe 3 O and MnGe 4 O Clusters: Anion Photoelectron Spectroscopy and Ab Initio Calculations.

The structures, chemical bonding, and magnetic properties of MnGe 3 O -/0 and MnGe 4 O -/0 are investigated by photoelectron spectroscopy and ab initio calculations. The experimental vertical electron detachment energies of MnGe 3 O - and MnGe 4 O - are measured to be 2.06 ± 0.04 and 2.64 ± 0.04 eV, respectively. The structures of MnGe 3 O -/0 and MnGe 4 O -/0 can be viewed as evolved from quadrilateral MnGe 3 or tetrahedral MnGe 3 . It is found that both MnGe 3 O - and MnGe 3 O have C s symmetric planar structures with an O atom attached to quadrilateral MnGe 3 . The structure of MnGe 4 O - is nonplanar with an O atom and an additional Ge atom attached to tetrahedral MnGe 3 , while that of MnGe 4 O is planar with an O atom and an additional Ge atom attached to quadrilateral MnGe 3 . Chemical bonding analyses reveal the existence of Ge═O double bonds in MnGe 3 O and MnGe 4 O. Magnetic property analyses suggest that MnGe 3 O and MnGe 4 O are ferromagnetic with total spin magnetic moments of 5 μ B .