AgmRhn clusters with m + n ≤ 55

Using a combination of genetic algorithms for the unbiased structure optimization and a Gupta many-body potential for the calculation of the energetic properties of a given structure, we determine the putative total-energy minima for all AgmRhn clusters with a total number of atoms m+n up to 55. Subsequently, we use various descriptors to analyze the obtained structural and energetic properties. With the help of a similarity function, we show that the pure Ag and Rh clusters are structurally similar for sizes up to around 20 atoms. The same approach gives that the mixed clusters tend to possess a larger structural similarity with the pure Rh clusters than with the pure Ag clusters. However, for clusters with m≃n≥25, other structures dominate. The effective coordination numbers for the Ag and Rh atoms as well as the radial distributions of those atoms indicate that there is a tendency towards segregation with Rh atoms forming an inner part and the Ag atoms forming a shell. Only few clusters, all with a fairly large total number of atoms, are found to be particularly stable

Mononuclear and dinuclear heteroleptic Cu(I) complexes based on pyridyl-triazole and DPEPhos with long-lived excited-state lifetimes

A mononuclear and two dinuclear heteroleptic Cu(I) complexes have been successfully prepared, using the chelating bis [(2-diphenylphosphino)phenyl] ether (DPEPhos) and pyrid-2'-yl-1H-1,2,3-triazole as chelating ligands. They show good luminescence in solution at room temperature with long-lived excited states. Furthermore, bimolecular quenching experiments of these new complexes with the catalyst Ni(cyclam)Cl-2 encourage the use of such compounds as photosensitizers for the photoreduction of carbon dioxide. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe

Firm heterogeneity and wages under different bargaining regimes : does a centralised union care for low-productivity firms?

This paper studies the relationship between wages and the degree of firm heterogeneity in a given industry under different wage setting structures. To derive testable hypotheses, we set up a theoretical model that analyses the sensitivity of wages to the variability in productivity conditions in a unionsised oligopoly framework. The model distinguishes centralised and decentralised wage determination. The theoretical results predict wages to be negatively associated with the degree of firm heterogeneity under centralised wage-setting, as unions internalise negative externalities of a wage increase for low-productivity firms. We test this prediction using a linked employeremployee panel data set from the German mining and manufacturing sector. Consistent with our hypotheses, the empirical results suggest that under industry-level bargaining workers in more heterogeneous sectors receive lower wages than workers in more homogeneous sectors. In contrast, the degree of firm heterogeneity is found to have no negative impact on wages in uncovered firms and under firm-level contracts

Globale Optimierungen in Clustern

In this work, we have studied the growth of several cluster systems including metallic and semiconductor clusters with our genetic algorithm coupled to the density functional tight- binding method followed by a re-optimization with density functional theory methods. Cadmium clusters with sizes up to 60 atoms form undistorted and symmetric clusters with a structural motif known as ”Leary-Tetrahedron”. Their stabilities correlate with their atomic configuration and the closing of electronic shells at certain sizes while their chemical bonds are quite similar to hcp-cadmium. Afterwards we studied the growth of mixed Si- Ge clusters with up to 30 atoms. The most stable clusters were found to be prolate with an average silicon content of 32-atom%. We found no structural similarities between pure and mixed clusters and the type of segregation depends on their individual composition. A correlation analysis showed no simple relations between structural features and electronic properties. At last we studied structural and magnetic properties of mixed AgRh n-1 and Ag n-1 Rh clusters with up to 20 atoms. Rhodium atoms within the polyicosahedral clusters were found to occupy positions in the center of the clusters. On the other side a silver atom migrates to the surface of rhodium-rich clusters. Local magnetic moments in the Ag n-1 Rh clusters are mainly localized on the single rhodium atom and depend upon its coordination number. A single foreign silver atom in rhodium clusters on the other side does not contribute to the total magnetic moment.Die vorliegende Arbeit untersucht das Wachstum von kleinen bis mittelgroßen Metall- und Halbleiterclustern. Kandidaten für globale Minima wurden mit einem genetischen Algo- rithmus optimiert und mit Dichtefunktionalmethoden untersucht. Cadmium Cluster mit bis zu 60 Atomen bilden unverzerrte, symmetrische Cluster mit einem Strukturmotiv, das als ”Leary-Tetraeder” bekannt ist. Relative Stabilitäten ergeben sich aus geometrischen Effekten und dem Schließen von Elektronenschalen. Die Bindungsverhältnisse sind ähn- lich zum Bulk. Anschließend wurde das Wachstum von Silizium-Germanium Cluster mit bis zu 30 Atomen untersucht. Relative Stabilitäten der Cluster hängen von deren Form und Zusammensetzung ab. Die stabilsten Cluster sind länglich und besitzen einen mittleren Siliziumgehalt von 32 Atom-%. Gemischte Cluster besitzen keine strukturelle Ähnlichkeit mit reinen Clustern und deren Segregationstyp ist von der Zusammensetzung abhängig. Es konnte kein Zusammenhang zwischen strukturellen und elektronischen Eigenschaften gefunden werden. Zuletzt wurden strukturelle und magnetische Eigenschaften von AgRh n-1 und Ag n-1 Rh Clustern mit einer Größe bis zu 20 Atomen untersucht. In den polyikosaedrischen Clustern Ag n-1 Rh besetzt ein Rhodiumatom eine Position im Clusterinneren. Im umgekehrten Fall migriert das Silberatom an die Oberfläche. Lokale magnetischen Momente in den Ag n-1 Rh Clustern sind auf dem Rhodiumatom lokalisiert und von dessen Koordinationszahl abhängig. In rhodiumreichen Clustern trägt ein einzelnes Silberatom nicht zum gesamtmagnetischen Moment bei

Wage distributions by bargaining regime

Collective wage bargaining, Wage structure, German Structure of Earnings Survey, Tariflohnverhandlungen, Lohnstruktur, Gehalts- und Lohnstrukturerhebung,