Author:

Keywords:

Science & Technology, Physical Sciences, Optics, Physics, Atomic, Molecular & Chemical, Physics, PARALLEL GENETIC ALGORITHM, CARBON-MONOXIDE ADSORPTION, DFT GLOBAL OPTIMIZATION, SIMPLE METAL-CLUSTERS, GAS-PHASE, NANOCLUSTERS, SUPERATOMS, VALENCE, NANOPARTICLES, DISSOCIATION, 01 Mathematical Sciences, 02 Physical Sciences, 03 Chemical Sciences, General Physics, 34 Chemical sciences, 49 Mathematical sciences, 51 Physical sciences

Abstract:

We analyze in detail how the interplay between electronic structure and cluster geometry determines the stability and the fragmentation channels of single Pd doped cationic Au clusters, PdAu_{N-1}^+ (N=2−20). For this purpose, a combination of photofragmentation experiments and density functional theory calculations was employed. A remarkable agreement between the experiment and the calculations is obtained. Pd doping is found to modify the structure of the Au clusters, in particular altering the 2D to 3D transition size, with direct consequences on the stability of the clusters. Analysis of the electronic density of states of the clusters shows that, depending on cluster size, Pd delocalizes one 4d electron, giving an enhanced stability to PdAu_6^+, or remains with all 4d^{10} electrons localized, closing an electronic shell in PdAu_9^+. Furthermore, it is observed that for most clusters, Au evaporation is the lowest-energy decay channel, although for some sizes Pd evaporation competes. In particular, PdAu_7^+ and PdAu_9^+ decay by Pd evaporation due to the high stability of the Au_7^+ and Au_9^+ fragmentation products.