Geometric evolution, electronic structure, and vibrational properties of ScGe _n ⁻ ( n = 6–17) anion clusters: A DFT insight

Abstract A comparison of theoretical and experimental properties is the most effective strategy for determining the global minimum (GM) because there is no experimental method to directly test the GM structure of clusters by now. The molecular and electronic structures and properties of Sc‐doped germanium anion clusters were explored via quantum chemistry calculations using mPW2PLYP scheme and unprejudiced structural searching technique ABCluster. Isomers are determined by ABCluster structural searches, followed by reoptimization of a great number of candidate geometries. The simulated photoelectron spectra for the GM structures match with those measured in experiment, suggesting that the current most stable structures are existence in the experiment. The molecular structural evolution modes appear as follows: as the cluster size n increases, the growth patterns are from the Sc‐linked geometry ( n = 10, 11) in which the Sc atom acts as a linker (Sc atom connects two Ge sub‐clusters) to the Sc‐encapsulated form ( n = 13–17) in which the Sc atom is settled in the core of the Ge‐cage framework. Besides, the properties including stability, HOMO‐LUMO gap, charge transfer, IR, Raman, and UV–Vis spectra were calculated. The Raman spectra are red‐shifted from the Sc‐linked to Sc‐encapsulated configurations. The analyses of stability, HOMO‐LUMO gap, and UV–Vis spectra revealed that the ScGe 16 − nanocluster could be the most suitable building block for further development as potential optoelectronic materials such as solar cell.