Browsing by Author "Schulz, B."

Large-scale coupled cluster calculations have been carried out for linear SiC8, a molecule of interest to astrochemistry. An accurate equilibrium structure has been established and a large equilibrium dipole moment of mu(e) = -9.96 D is predicted, where the positive end of the dipole is located at the silicon site. Most promising for future detection by infrared spectroscopy are the stretching vibrations at 1973 and 2103 cm(-1) with absolute intensities of 6662 and 3699 km mol(-1), respectively. The lowest bending vibration has a harmonic wavenumber of 38 cm(-1). The collinear fragmentation process SiC8 --> SiC6 + C-2 has been investigated and the corresponding dissociation energy is predicted to be D-0 = 568 kJ mol(-1).

On the basis of CCSD(T) calculations, an accurate equilibrium geometry (uncertainties in bond lengths: ca. 0.0005 Angstrom) has been established for linear HC3P. The CP equilibrium bond length is 1.5515 Angstrom and thus slightly longer than in HCP. Harmonic vibrational wavenumbers, vibration-rotation coupling constants and l-type doubling constants are reported. Accurate groundstate rotational constants are predicted for C-13 substituted species. (C) 2000 Elsevier Science B.V. All rights reserved.

New U–Pb and Lu–Hf detrital zircon data together with whole-rock geochemical and Sm–Nd data were obtained for paragneisses of the Austroalpine basement south of the Tauern Window. Geochemically immature metasediments of the Northern–Defereggen–Petzeck (Ötztal–Bundschuh nappe system) and Defereggen (Drauzug–Gurktal nappe system) groups contain zircon age populations which indicate derivation mainly from Pan-African orogens. Younger, generally mature metasediments of the Gailtal Metamorphic Basement (Drauzug–Gurktal nappe system), Thurntaler Phyllite Group (Drauzug–Gurktal nappe system) and Val Visdende Formation (South Alpine Basement) were possibly derived from more distant sources. Their significantly larger abundances of pre-Pan-African zircons record a more advanced stage of downwearing of the Pan-African belts and erosion of older basement when the Austroalpine terrane was part of the Early Palaeozoic Northern Gondwana passive margin. Most zircon age spectra are dominated by Ediacaran sources, with lesser Cryogenian, Tonian and Stenian contributions and subordinate Paleoproterozoic and Neoarchean ages. These age patterns are similar to those recorded by Cambro–Ordovician sedimentary sequences in northeastern Africa between Libya and Jordan, and in some pre-Variscan basement inliers of Europe (e.g. Dinarides–Hellenides, Alboran microplate). Therefore, the most likely sources seem to be in the northeastern Saharan Metacraton and the Northern Arabian–Nubian Shield (Sinai), further supported by whole-rock Sm–Nd and zircon Lu–Hf data.

We report psychophysical experiments and time series analyses to investigate sensorimotor tapping strength fluctuations in human periodic tapping with and without a metronome. The power spectral density of tapping strength fluctuations typically decays in an inverse power law (1/fβ-noise) associated with long-range correlations, i.e., with a slow power-law decay of tapping strength autocorrelations and scale-free behavior. The power-law exponents β are scattered around β=1 ranging from 0.67 to 1.8. A log-linear representation of the power spectral densities reveals rhythmic peaks at frequencies f=0.25 (and f=0.5) and a tendency to slightly accentuate every fourth (and second) stroke when subjects try to synchronize their tapping with a metronome.