Die Kristallstruktur von CsTcO4 [1]

The Crystal Structure of CsTcO₄ CsTcO₄ crystallizes orthorhombic with a = 5.72₇, b = 5.92₁ and c = 14.34 Å. Z = 4, space group Pnma (Nr. 62, I.T.). The metal positions were refined by single crystal data, the oxygen positions first determined: the CsTcO₄ structure is a slight distortion of the scheelite arrangement (parameters: see text). The MADELUNG Part of Lattice Energy, MAPLE, ?Mean Effective Ionic Radii”?, MEIR, and Effective Coordination Numbers, ECoN, are calculated and discussed.     

Microsatellite structures in the context of human evolution

Six microsatellite - or short tandem repeat (STR) - systems with uniform repetitive sequences (HumTH01, HumCD4, HumFES/FPS, HumF13B, HumTPO, HumLPL) and three compound repeat systems (HumVWA, HumFIBRA, D21S11) were used, including data from the literature, to determine genetic distances among eight populations worldwide. The TH01- and VWA homologous loci in nonhuman primates (chimpanzees, gorillas, orangutans, rhesus monkeys, ring-tailed lemurs) were compared and found to be shorter than in humans. Microsatellites of lower complexity were most efficient for the separation of major ethnic groups. The loci of higher complexity showed a leveling of the diversity differences among populations, which could be attributed to higher mutation rates.     

Numerical computation of the electrostatic interaction energy between methanol and the dyad water-imidazole

Summary The electrostatic interaction energy between methanol and the dyad water-imidazole has been computed numerically at three levels of approximation from 3D grids of the charge density of one partner and the electrostatic potential of the other. The minimum positions and energy values thus obtained compare well with those calculated analytically. The numerical procedure is especially interesting for the prediction of the stable conformers.     

Molecular approaches to solar energy conversion with coordination compounds anchored to semiconductor surfaces

Strategies toward the realization of molecular control of interfacial charge transfer at nanocrystalline semiconductor interfaces are described. Light excitation of coordination compounds, based on (dpi)6 transition metals, anchored to wide band-gap semiconductors, such as TiO2, can initiate electron-transfer processes that ultimately reduce the semiconductor. Such photoinduced charge-separation processes are a key step for solar energy conversion. The thermodynamics and kinetic rate constants for three different interfacial charge separation mechanisms are discussed. Tuning the energetic position of the semiconductor conduction band relative to the molecular sensitizer has provided new insights into interfacial charge transfer. Supramolecular compounds that efficiently absorb light, promote interfacial electron transfer, and feature additional functions such as intramolecular electron transfer when bound to semiconductor surfaces have also been studied. New approaches for enhancing charge-separation lifetimes for solar energy conversion are presented.     

The application of INAA to the geochemical analysis of single diamonds

Instrumental neutron activation analysis (INAA) has been applied to the analysis of 62 small (0.01–0.5 carat), single, inclusion-bearing and inclusion-free diamonds from South Africa, Brazil and Colorado. Up to 40 elements were detected at the ppb and ppt levels in individual diamonds of the eclogitic (basaltic affinity) and the peridotitic (ultramafic) paragenesis. The data obtained in this study can be used to distinguish between diamonds from the eclogitic and peridotitic parageneses and provides geochemical information on the environment in which diamonds crystallize. Further, the technique may prove to be useful in fingerprinting diamonds of different provenance areas.