A Raman spectral analysis of the ammonium iodide—dioxane complex

The solid state complex between ammonium iodide and 1,4-dioxane has been found by TGA studies to be a ($\text{1}\text{1}$) adduct rather than a ($\text{1}\text{2}$) adduct as previously formulated. The laser Raman spectra of NH₄I· dioxane and ND₄I· dioxane in the N-H and N-D stretching regions show decreases in frequency compared to NH₄I and ND₄I which are consistent with hydrogen bonding of the N-H · O variety as a means of incorporation of the dioxane into the salt crystal lattice.     

Electric field gradient models based on the geometry of the coordination sphere

A complication in NQR studies of many organometallic complexes of contemporary interest is the low molecular symmetry. Guidance is needed on the principal axis orientation and geometric effects of the electric field gradient. In this paper a “coordination sphere” model based on electrostatic charges is described for the fac-a₃b₂c, fac-a₃b₂ ligand geometries. Experimental tests are made using e²Qq/h and η for a number of organometallic Co and Mn complexes having these geometries. The model is surprisingly successful if b and c are single-atom donor ligands. π-Olefin and some other strong π-acceptor ligands yield poorer results. The coordination sphere model is a useful augment to the Townes-Dailey model.     

Instability of closed spaces in general relativity

There are strong restrictions on the solutions of the initial value constraints of General Relativity when the spatial hypersurface is closed. In particular, closed flat space is unstable: not all solutions of the linearized constraints correspond to nearby solutions of the constraints themselves. For example, no nearby solutions whatever exist which are time symmetric. Other restrictions, which limit perturbations of non-flat closed initial solutions, are also exhibited.Supported in part by the National Science Foundation and by the Humboldt-Foundation.Supported in part by Grant AFOSR 70-1864.     

Isolated maximal surfaces in spacetime

Maximal surfaces and their implications for the ambient spacetime are studied. Our methods exploit the interplay between contact of the volume functional and energy conditions. Essentially, we find that in closed universes, maximal surfaces are unique; they maximize volume; and they yield future and past singularities.Supported in part by the National Science Foundation under grant No. PHY 70-02077A03 and by the Humboldt FoundationSupported in part by the Sonderforschungsbereich (Theoretische Mathematik) of the University of Bonn     

Bestimmung von Kupfer,Zink, Zinn und Blei in Guß-Zinnbronze/Rotguß nach DIN 1705 und Guß-Bleibronze/Guß-Zinn-Bleibronze nach DIN 1716 durch Röntgenspektralanalyse wäßriger Probenlösungen

The paper describes the—as far as possible—automatic determination of carbon, hydrogen and nitrogen in the ultramicorange. The method is based on the Hewlett-Packard CHN-Analyzer. An electronic desk-calculator controlls the determination from weighing the substance, integrating the areas of the gaschromatographic separation of CO₂, H₂O and N₂ to printing the results by alphanumeric output.