Luminescence of dimeric Tl(I)-complexes: Metal-metal interaction in the electronically excited state

Summary Dimeric diethyldithiocarbamatethallium(I) [Et ₂NCS₂Tl]₂ shows a red emission at _max=608 nm which undergoes a huge Stokes shift with regard to the excitation maximum at =246 nm. It is suggested that the emission originates from a sp excited state which is characterized by strong metal-metal bonding.

---

Lumineszenz von dimeren Tl(I)-Komplexen: Metall-Metall-Wechselwirkung im elektronisch angeregten Zustand (Kurze Mitt.)

Zusammenfassung Dimeres Thallium(I)diethyldithiocarbamat [Et ₂NCS₂Tl]₂ zeigt eine rote Emission mit _max=608 nm und eine große Stokes'sche Verschiebung im Bezug auf das Anregungsmaximum von =246 nm. Die Emission wird einem sp angeregten Zustand zugeordnet, der durch eine starke Metall-Metall Wechselwirkung charakterisiert ist.

     

Stickstoffbestimmung

Ohne Zusammenfassung     

Triggered Fronts in the Complex Ginzburg Landau Equation

We study patterns that arise in the wake of an externally triggered, spatially propagating instability in the complex Ginzburg–Landau equation. We model the trigger by a spatial inhomogeneity moving with constant speed. In the comoving frame, the trivial state is unstable to the left of the trigger and stable to the right. At the trigger location, spatio-temporally periodic wave trains nucleate. Our results show existence of coherent, “heteroclinic” profiles when the speed of the trigger is slightly below the speed of a free front in the unstable medium. Our results also give expansions for the wavenumber of wave trains selected by these coherent fronts. A numerical comparison yields very good agreement with observations, even for moderate trigger speeds. Technically, our results provide a heteroclinic bifurcation study involving an equilibrium with an algebraically double pair of complex eigenvalues. We use geometric desingularization and invariant foliations to describe the unfolding. Leading-order terms are determined by a condition of oscillations in a projectivized flow, which can be found by intersecting absolute spectra with the imaginary axis.     

Large deformation and plates

In the simulation of deformations of plates it is well known that we have to use a special treatment of the thickness dependence. Therewith we achieve a reduction of dimension from 3D to 2D. For linear elasticity and small deformations several techniques are well established to handle the reduction of dimension and achieve acceptable numerical results. In the case of large deformations on plates with non-linear material behaviour there exist different problems. For example the analytical integration over the thickness of the plate is not possible due to the non-linearities arising from the material law and the large deformations themselves. There are several possibilities to introduce a hypothesis for the treatment of the plate thickness from the strong Kirchhoff assumption on one hand up to some hierarchical approaches on the other hand. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Deformation of striped patterns by inhomogeneities

We study the effects of adding a local perturbation in a pattern-forming system, taking as an example the Ginzburg–Landau equation with a small localized inhomogeneity in two dimensions. Measuring the response through the linearization at a periodic pattern, one finds an unbounded linear operator that is not Fredholm due to continuous spectrum in typical translation invariant or weighted spaces. We show that Kondratiev spaces, which encode algebraic localization that increases with each derivative, provide an effective means to circumvent this difficulty. We establish Fredholm properties in such spaces and use the result to construct deformed periodic patterns using the Implicit Function Theorem. We find a logarithmic phase correction, which vanishes for a particular spatial shift only, which we interpret as a phase-selection mechanism through the inhomogeneity. Copyright © 2013 John Wiley & Sons, Ltd.