Insights into the structure and growth of Lu-doped germanium clusters: comparing density functional theory calculations with photoelectron spectroscopy experiments

The structure and growth of a series of Lu-doped germanium clusters, LuGenq (n = 2-14, q = 0, -1) have been investigated by previous photoelectron spectroscopy (PES) and density functional theory (DFT) calculations. The ground states of the anionic LuGen- clusters obtained from DFT calculations are verified by comparing simulated PES with experimental results. The simulated PES for smaller clusters LuGen- (n <= 6) display relatively simple spectral patterns, suggesting high symmetry structures. It is observed that the pentagonal bipyramid shape is the basic framework for the nascent growth process of LuGen- (n = 2-8). The structures of LuGen- (n = 2-13) clusters are all exohedral structures with the Lu atom adsorbed at the surface of the bare Ge-n(-) clusters, while LuGe14- is the smallest endohedral Lu-doped germanium cluster with the Lu atom completely fallen into the germanium frame. It is found that the LuGen- clusters with even n are more stable than those with odd n and in the LuGen clusters there is an opposite trend. Especially, the LuGenq (n = 9, 12, q = 0, -1) clusters are extremely stable compared to other size clusters. HOMO-LUMO gap shows that the chemical stability of bare Ge-n(-) (n = 2-14) clusters are stronger than that of LuGenq (n = 2-14, q = 0, -1) clusters owing to the doping of a Lu atom.

Automated summary

The structure and growth of Lu-doped germanium clusters were investigated using photoelectron spectroscopy and density functional theory. The ground states of the anionic LuGen- clusters were verified by comparing simulated PES with experimental results. The pentagonal bipyramid shape was observed as the basic framework for the growth process of LuGen-.