Evolution of electronic and vibrational properties of M@X-n (M = Ag, Au, X = Ge, Si, n=10, 12, 14) clusters: a density functional modeling

Evolution of electronic and vibrational properties of M@X-n (M = Ag, Au, X = Ge, Si, n = 10, 12, 14) nanoclusters is investigated by using first-principle density functional theory (DFT)-based calculations with effective core potentials. To explain the thermodynamic and chemical stability of the ground state cluster in each size, variation of different thermodynamic and chemical parameters, like, binding energy (BE), HOMO-LUMO gap (Delta E), vertical ionization potential (VIP) and vertical electron affinity (VEA) was studied with the variation of the size of the clusters for emphasizing the differences and similarities in the clusters. It is found that Au doping in Ge and Si cages prefers endohedral position, whereas Ag prefers to take the position at the surface of the cages. In addition, IR and Raman spectra of the clusters are also studied to understand the vibrational nature of the stable clusters. At the end, present theoretical results are compared with existing experimental data. Theoretical knowledge of the thermodynamic, chemical and vibrational properties of these specific ground state structures is important for understanding its potential application in the field of optoelectronic science.