Structures and ionization energies of small lithium doped germanium clusters

• Published in: Physical chemistry chemical physics : PCCP Vol. 15; no. 14; pp. 5151 - 5162
• Main Authors: DE HAECK, Jorg, BA TAI, Truong, BHATTACHARYYA, Soumen, THUY LE, Hai, JANSSENS, Ewald, THO NGUYEN, Minh, LIEVENS, Peter
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 14.04.2013
• Subjects: Adiabatic flow; Atomic and molecular clusters; Atomic and molecular physics; Clusters; Computational efficiency; Electron affinity; Energy use; Exact sciences and technology; Ionization; Lithium; Physics; Studies of special atoms, molecules and their ions; clusters; Thresholds; Germanium; Lithium; Energy; Structure; Ionization; Atomic clusters
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c3cp44395g

We present a combined theoretical and experimental investigation of neutral and cationic lithium doped germanium clusters, GenLim (n = 5-10; m = 1-4). The vertical ionization energies and ionization thresholds are derived from threshold photoionization efficiency curves in the 4.68-6.24 eV range and are compared with calculated vertical and adiabatic ionization energies for the lowest energy isomers obtained using DFT computations. The agreement between experimental and computed values supports the identification of the ground state structures. Charge population analysis shows that lithium transfers its valence electron to the Gen hosts to form Gen(mδ-)-mLi(δ+) and Gen((mδ(-)+1))-mLi(δ+) complexes. This is also illustrated by the strong correlation between the size dependent lithium adsorption energies in GenLi and the Gen electron affinities. Neutral GenLim clusters are formed by adsorbing lithium atoms on either triangular or rhombic faces of the Gen framework with the lithium atoms tending to avoid each other. The chemical bonding phenomena of clusters are analyzed in detail using the densities of states and molecular orbitals.