Die gasförmigen Komplexe NiAl2Cl8 und NiAl3Cl11

Gaseous Complexes NiAl₂Cl₈ and NiAl₃Cl₁₁ Spectral photometric measurements of equilibria which are established by reaction of solid NiCl₂ with gaseous Al₂Cl₆ have been made. Results see ?Inhaltsübersicht”?.     

Para-Fluorination of Anilides Using Electrochemically Generated Hypervalent Iodoarenes

The para-selective fluorination reaction of anilides using electrochemically generated hypervalent ArIF₂ is reported, with Et₃N ⋅ 5HF serving as fluoride source and as supporting electrolyte. This electrochemical reaction is characterized by a simple set-up, easy scalability and affords a broad variety of fluorinated anilides from easily accessible anilides in good yields up to 86 %.     

Rational symplectic field theory for Legendrian knots

We construct a combinatorial invariant of Legendrian knots in standard contact three-space. This invariant, which encodes rational relative Symplectic Field Theory and extends contact homology, counts holomorphic disks with an arbitrary number of positive punctures. The construction uses ideas from string topology.     

Ein kombinierter Destillationsapparat

Ohne Zusammenfassung     

Combinatorial knot contact homology and transverse knots

We give a combinatorial treatment of transverse homology, a new invariant of transverse knots that is an extension of knot contact homology. The theory comes in several flavors, including one that is an invariant of topological knots and produces a three-variable knot polynomial related to the A-polynomial. We provide a number of computations of transverse homology that demonstrate its effectiveness in distinguishing transverse knots, including knots that cannot be distinguished by the Heegaard Floer transverse invariants or other previous invariants.     

Stabilized diode laser pumped, idler-resonant cw optical parametric oscillator

We present a diode laser pumped continuous wave, pump-enhanced singly-resonant optical parametric oscillator (OPO). The cavity is stabilized by a Pound?CDrever?CHall scheme using direct modulation of the diode laser. The system provides stable signal powers of up to 220?mW. The wavelength can be tuned between 1.40?C1.60???m for a ring or a linear cavity design by changing the crystal temperature. The relative fluctuations of the stabilized OPO??s wavelength are less than 10^?7 for more than one hour. Using a self-heterodyne technique, we measure a linewidth of the signal wave of 3.5?MHz.     

An EPR study of two-electron sensitization by fragmentable electron donors

Fragmentable electron donors (FEDs) are molecules designed to undergo bond fragmentation after capturing the hole created by photoexposure of silver halide. By design, the radical remaining after fragmentation is a potent reductant expected to be capable of injecting an electron into the conduction band of the silver halide. Thus, the addition of a FED to the AgX surface should allow the creation of two electrons for each photon absorbed by the substrate. Photographic studies have confirmed that the addition of FEDs can increase the photosensitivity of AgX materials. In this work, EPR spectroscopy was employed to study the processes of hole capture, donor fragmentation, and secondary electron injection by FEDs in AgBr dispersions. To do so, we used AgBr microcrystals doped with diamagnetic transition metal complexes that act as deep electron traps. For samples exposed to actinic light at 15 K, secondary electron injection was detected as an increase in the EPR signal from electrons trapped at the dopant upon annealing the samples above 50 K. Organic radical intermediates and self-trapped hole centers were the other paramagnetic species monitored in this study. The results presented here confirm that the FED sensitization mechanisms originally proposed by Gould et al. take place at silver halide surfaces and result in additional electrons in the silver halide conduction band.