The geometrical structures, relative stabilities, electronic and magnetic properties of small Pd n Ir (n = 1-8) clusters have been systematically investigated using density functional theory at the B3PW91 level. The optimised geometries show that the lowest-energy structures of Pd n Ir clusters prefer a three-dimensional configuration. The relative stability of these clusters was examined by analysis of the binding energies per atom, fragmentation energies, the second-order difference of energies and the HOMO-LUMO energy gaps as a function of cluster size. The obtained results exhibit that the Pd 2 Ir, Pd 3 Ir and Pd 5 Ir clusters are more stable than their neighbouring clusters. The energy gap of the Pd 2 Ir cluster is the largest of all the clusters (2.258 eV). In addition, the charge transfers, vertical ionisation potentials, vertical electron affinities and chemical hardness were calculated and discussed. The magnetism calculations indicate that the total magnetic moment of Pd n Ir clusters is mainly localised on the iridium atom for Pd 1-6 Ir clusters. Meanwhile, the 5d orbital plays the key role in the magnetic moment of the iridium atom.

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A theoretical study of 3-(4-Chlorophenyl)-1,1-dimethylurea and its protonated isomers has been carried out, to emphasize the experimental results of the electrostatic interactions in the herbicide models, for investigating the implications taking place on the structural parameters starting from the gaseous phase to the aqueous one. It has been found that its functionalized structure gives us three protonated targets. The calculations has been performed on both neutral and protonated forms using Density Functional Theory (DFT) with the hybrid functional B3LYP. Many molecular parameters have been studied. To identify the reactive sites, our study has focused on the local and the global reactivity descriptors explaining the chemical reactivity. The calculations have demonstrated that the attacks on the aliphatic branched exocyclic positions are privileged to those of the aromatic ring. Studying the solvent effect has revealed that there is a change in the hierarchy of the electrophilicity. Various vibrational modes have been exploited to discuss the literary spectroscopic data.

The equilibrium geometries, relative stabilities, electronic and magnetic properties of small RhnCa (n = 1–9) clusters have been investigated by DFT calculations. The obtained results show that the three‐dimensional geometries are adopted for the lowest‐energy RhnCa clusters, and the doped Ca atom prefers locating on the surface of the cluster. Based on the analysis of the second‐order difference of energies, fragmentation energies and the HOMO‐LUMO energy gaps, we identify that the Rh4Ca, Rh6Ca, and Rh8Ca clusters are relatively more stable than their neighboring clusters, and the doping of Ca enhances the chemical reactivity of the pure Rhn clusters, suggesting that the RhnCa clusters can be used as nanocatalysts in many catalytic reactions. The magnetic moment for these clusters is mostly localized on the Rh atoms, and the doping Ca atom has no effect on the total magnetic moment of RhnCa clusters. The partial density of states, VIP, VEA, and η of these clusters in their ground‐state structures were also calculated and discussed. © 2015 Wiley Periodicals, Inc.