A quantitative measure of bond polarity from the electron localization function and the theory of atoms in molecules

 A quantitative measure of the polarity of a bond can be obtained through combining the two complementary topological partitionings of the electron density obtained from the atoms in molecules theory, on the one hand, and the electron localization function, on the other. This requires an integration of the electron density in the atomic subbasins of a common bond electron localization basin. We present the first numerical application of the resulting topological definition of bond polarity to a set of small linear systems consisting of the FCN, HF, HCl, HBr, and NaCl molecules and the NeAr van der Waals dimer. It is shown that the findings are essentially in line with common expectation for these simple molecules, thus confirming the potential value of the novel bond polarity index for the analysis of controversial bonding situations. Additional insight is provided through the detailed investigation of fluctuations in the basin populations. Received: 10 January 2001 / Accepted 12 February 2001 / Published online: 22 May 2001     

Na10Zn4O9 – ein neues Oxozinkat mit trigonal-planar koordiniertem Zink

Na₁₀Zn₄O₉, a Novel Oxozincate with Trigonal Planar Coordinated Zinc Using a new preparation method for sodium oxometallates we have succeeded in the synthesis of the new ternary oxide Na₁₀Zn₄O₉. Active ZnO reacted with Na₂O generated in situ from NaN₃ and NaNO₂. The compound consists of ZnO₄ tetrahedra which are connected via edges and corners to form layers of the composition ZnO₂. Furthermore, the structure was found to contain isolated, trigonal planar ZnO₃ units. 21 of 60 Na⁺ ions within the unit cell are disordered. Na₁₀Zn₄O₉ crystallizes in the space group R3 m (Nr. 166). The lattice constants are: a = 10.815(3), c = 17.930(7) Å; Z = 6; 8056 reflections; R = 0.062. The sodium ion conductivity at 400°C is 6 × 10^?3 Ω^?1 cm^?1.     

Presentation of sideband envelopes by two-dimensional one-pulse (TOP) spectroscopy.

A novel way of representing 1D MAS spinning sideband spectra in a 2D-resolved fashion is explained. The method is illustrated with 2H MAS data of deuterated polycarbonate. From the resulting 2D spectrum, the isotropic shifts can be identified on one axis and the rotary echo decay spectra along the other axis.     

Mass-transfer analysis of a:Si:H deposition by the glow discharge process

The deposition rate and the gas efficiencies in the glow discharge plasma process are calculated by solving the convective diffusion equations for the precursor gas and the condensable species which are created by the discharge. The theoretical predictions are compared with experimental results obtained with a cross-flow reactor.