Two magnon light scattering in K2MnF4

The light scattering spectra of the two dimensional Heisenberg antiferromagnet K₂MnF₄ are reported. At low temperatures a two magnon band is observed and four bands due to phonons as well.     

Pade-Approximants for the Electron Gas and for Symmetrical Plasmas

The range of validity for several Pade-formulae for thermodynamic functions is checked in comparison with most recently available numerical data. Landscapes of maximum deviation are plotted. Application to symmetrical electron-positron and electron-hole plasmas is performed. An evaluation of the critical data for the droplet transition in semiconductors is given.     

On the index of a holomorphic vector field tangent to a singular variety

In this article we define and compute an index for a holomorphic vector field on a (possibly singular) subvariety of a complex manifold, provided the subvariety is a local complete intersection. This index reduces to the usual Poincaré-Hopf index in case the subvariety is smooth, and is equal more generally to the index defined in [GSV] and [SS].     

EPR and luminescence of Mn2+ in MgF2 single crystals

EPR spectra of Mn²⁺ in MgF₂ crystals grown by the Bridgman technique were measured at 300 and 20 K. Application of the superposition model to the zero field splitting (ZFS) patterns indicates complete absence of dynamic contributions to the ZFS. The luminescence spectra are also in accord with substitutional incorporation of Mn²⁺.     

Über die Tribromomangan(II)-Säure und deren Komplex mit Pyridin

Tribromomanganese(II) acid has been prepared for the first time and will be described. A complex of the acid with pyridine was obtained and its UV, visible, IR and¹H-NMR spectra will be reported.     

On the superpropagator of fields with exponential coupling

We define the vacuum expectation value of the time-ordered product of two exponentials of free fields as a distribution using minimal singularity as a criterion. The implication of this definition for an exponentially self-coupled scalar field is studied in second order of a perturbation expansion.     

Einige Betrachtungen zur Beschreibung von Vorgängen in der klassischen Kontinuumsmechanik

Ohne Zusammenfassung     

Development of three-dimensional microstructure processing using macroporousn-type silicon

The development of a micromachining technique for processing arbitrary structures with high aspect ratios in bulk silicon is presented. It is based on utilizing standard microelectronic processes and electrochemical macropore formation onn-type silicon in electrolytes containing hydrofluoric acid. This pore-etching technique allows us to produce very regular pore arrays with pore diameters and distances in the micrometer range and pore lengths up to wafer thickness. Samples with prefabricated pore arrays which differ in pore spacing, pore diameter and geometry are used as substrates for a micromachining process. The pores will facilitate the anisotropic etch profile which is required for the desired high aspect ratios although an isotropic etch process is used. Very deep microstructures with steep pore walls and aspect ratios of 10–15 are produced with this technique. It is shown that smaller pore array dimensions improve microstructure resolution.