Protonenresonanz-Spektroskopische Untersuchungen am Acetyl-cyclobutadien-eisentricarbonyl. Ein Beitrag zur Kenntnis der Bindungsverhältnisse im Komplex Gebundenen Cyclobutadien

The proton magnetic resonance spectrum of acetyl-cyclobutadiene-irontricarbonyl has been measured including all observable ¹³C? H-coupling constants. The couplings are assigned and discussed with respect to structure and bonding properties of the molecule. The results exclude the structure of a cyclic conjugated diene with alternating double and single bonds.     

Associativity in volume holography

We show theoretically and experimentally that associative connections between image structures are performed with advantage in thick media.     

Image guide couplers with isotropic and anisotropic coupling elements

Among other waveguide elements directional couplers are required in integrated millimeterwave circuits in image guide technique. Hereby an I-guide is used which consists of a dielectric slab between two conducting plates on which the electric field is perpendicularily. Flat coupling behaviour and better isolation can be reached by use of a dielectric coupling element and absorber materials. Thereby the frequency dependence is reduced significantly. Further the coupling can be steered by an additional premagnetized ferrite slab. In this way switched couplers can be realized.     

Renormalized shell model matrix elements derived from nucleon-nucleon phase shifts

We apply theG matrix elements calculated by Singh et al. (using the DWBA approach) to some spectra calculations forA=18, 19, 20 after first renormalizing the matrix elements by including second-order processes inG. The corrections introduced by the Distorted-Wave-Born-Correction Term are attractive for both the H.J. and Reid potentials. The magnitude and uncertainties in these corrections are discussed. Differences between these potentials are attributed chiefly to their different off-the-energy-shell behaviour. The results are compared to calculations with the Kuo matrix elements and with experiment.     

Einfluß der chemischen Bindung auf die Lα1,2− und Lβ1− Röntgenemissionsspektren des Arsens

The As Lα_1,2 and Lβ₁ X-ray emission spectra from metallic arsenic and from the compounds As₂O₃, Na₂HAsO₄·7H₂O, and GaAs were measured with high resolution and fluorescence excitation. The shape of the spectra and correlation between the chemical shifts of the Lα lines (0·1, ? 0·22 and ? 0·05 eV in As₂O₃, Na₂HAsO₄·7H₂O, and GaAs resp.) and atomic charges are discussed.     

New Transition Metal Oxo‐Thiostannate: Synthesis,Characterization, and Investigation of its Photocatalytic Properties

The new transition metal oxo‐thiostannate {[Ni(cyclen)]₆[Sn₆S₁₂O₂(OH)₆]} · 2(ClO₄) · 19H₂O ( 1 ) was prepared under hydrothermal conditions using Na₄SnS₄ · 14H₂O and [Ni(cyclen)](ClO₄)₂ as reactants. In the crystal structure the rare [Sn₆S₁₂O₂(OH)₆]^10– anion is observed, which is composed of SnS₂O(OH)₃ and SnS₄O₂ octahedra, and SnS₄ tetrahedra sharing edges and corners. The anion is expanded by six Ni²⁺ centered complexes via Ni–S and Ni–OH bonds. The photocatalytic properties for the visible light driven hydrogen evolution reaction shows that 26.6 mmol · g^–1 H₂ were evolved after 3 h.