Permethylcyclohexane

Permethylcyclohexane 2 has been synthesized and investigated by dynamic NMR spectroscopy. An unexpectedly low barrier (ΔG3₃₃₃ = 70.0 kJ/mol) of its chair-to-chair interconversion was found.     

Kontrahierbare analytische Algebren

Ohne Zusammenfassung     

Solutions of the anti-self-dualSU(2) Yang-Mills equations gained from the inverse scattering method

By applying the inverse scattering method in connection with a dressing procedure a huge class of solutions of the anti-self-dualSU(2) Yang-Mills equation is obtained. This class contains also the well-known't Hooft instantions.     

Über die Modultransformation einer Halbgitterfunktion

Ohne Zusammenfassung     

Application of Landau's theory of Fermi Liquids to nuclear matter

Landau's theory of Fermi Liquids is applied to the hydrodynamic model of the giant resonance. It is shown that for reasonable range parameters of the effective force only thes- andp-wave contributions are important. The theory then can be characterized by four constants: thef-sum (including exchange corrections), the symmetry energy, the Fermi energy, and the effective mass. In heavy nuclei the Coulomb force has also to be taken into account. It leads to a shift of the position of the giant resonance by about 10 to 15%.     

Laserspektroskopie

X-Ray spectra and chemical binding     

Possible pathways of CVD processes leading to III-V semiconductors via a two-dimensional growth.

Quantum-chemical calculations were carried out to shed more light upon possible first intermediates formed during chemical vapour deposition (CVD) processes leading to III-V semiconductors. Information about possible structures of intermediates and about thermodynamic properties in dependence of the temperature were collected. Because some of the systems calculated herein contain a substantial number of atoms (up to 144), it is limited to intermediates on the way to solid AIN. According to our suggestion, the first intermediates are species with the overall formula AINH2, Al2N2H4, Al3N3H6, AI5N5H8, AI7N7H, and Al9N9H, AI12N12H12. In further calculations the growth of a second layer, on top of the first layer, which is modelled by the Al12N12H12 cluster, is simulated. The Al12N12H12 "surface" offers two places for the attachment of an Al3N3H6 ring. At temperatures of 1000 K, the deltaG value for this attachment is only slightly negative, which suggests that the molecules can move relatively freely on the surface. This might be of importance for a defect-free growth process. Up to four layers are built on top of the first Al12N12H12 layer leading to Al24N24H24 (two layers), Al36N36H36 (three layers) and Al48N48H48 (four layers). The structures are compared with that of solid AIN in its most stable Wurzit-type structure.     

Ein Satz über geodätische Verbindbarkeit in normalhyperbolischen Räumen

Under certain conditions, two points of a normal hyperbolic manifold joined by a time-like curve can be joined by a time-like geodesic. These conditions are discussed, and some applications are given.