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1,219 results on '"Schmid G"'

2. All-XUV Pump-Probe Transient Absorption Spectroscopy of the Structural Molecular Dynamics of Di-iodomethane

Author

Rebholz, M, Ding, T, Despré, V, Aufleger, L, Hartmann, M, Meyer, K, Stooß, V, Magunia, A, Wachs, D, Birk, P, Mi, Y, Borisova, GD, Castanheira, CDC, Rupprecht, P, Schmid, G, Schnorr, K, Schröter, CD, Moshammer, R, Loh, ZH, Attar, AR, Leone, SR, Gaumnitz, T, Wörner, HJ, Roling, S, Butz, M, Zacharias, H, Düsterer, S, Treusch, R, Brenner, G, Vester, J, Kuleff, AI, Ott, C, and Pfeifer, T

Subjects
Astronomical and Space Sciences, Condensed Matter Physics, Quantum Physics
Abstract

In this work, we use an extreme-ultraviolet (XUV) free-electron laser (FEL) to resonantly excite the I: 4d5/2-σ∗ transition of a gas-phase di-iodomethane (CH2I2) target. This site-specific excitation generates a 4d core hole located at an iodine site, which leaves the molecule in a well-defined excited state. We subsequently measure the time-dependent absorption change of the molecule with the FEL probe spectrum centered on the same I: 4d resonance. Using ab initio calculations of absorption spectra of a transient isomerization pathway observed in earlier studies, our time-resolved measurements allow us to assign the timescales of the previously reported direct and indirect dissociation pathways. The presented method is thus sensitive to excited-state molecular geometries in a time-resolved manner, following a core-resonant site-specific trigger.

Published
2021

5. Oxidation-Resistant Gold-55 Clusters

Author

Kästle, C., Weigl, F., Koslowski, B., Dietrich, C., Ziemann, P., Spatz, J. P., Riethmüller, S., Hartmann, C., Möller, M., Schmid, G., Garnier, M. G., and Oelhafen, P.

Published
2002

31. Schooling mediates brain reserve in Alzheimer's disease: findings of fluoro-deoxy-glucose-positron emission tomography

Author

Perneczky, R., Drzezga, A., Diehl-Schmid, J., Schmid, G., Wohlschlager, A., Kars, S., Grimmer, T., Wagenpfeil, S., Monsch, A., and Kurz, A.

Subjects
Alzheimer's disease -- Development and progression, Alzheimer's disease -- Research, Brain -- Physiological aspects, PET imaging -- Research, Education, Higher -- Research, Health, Psychology and mental health
Published
2006

33. Measuring Vertical Distribution and Dynamic Development of Sediment Infiltration under Laboratory Conditions.

Author

Mayar, M. A., Haun, S., Schmid, G., Wieprecht, S., and Noack, M.

Subjects
SEDIMENTS, PARTICLE size distribution, RIVER channels, SPATIAL resolution, SUPPLY & demand
Abstract

The complex process of sediment infiltration in gravel beds has been studied widely. However, the temporal behavior of sediment infiltration and its clogging has not yet been investigated sufficiently. To understand the mechanisms involved in this phenomenon, measurements of the effects of various boundary conditions are required with high spatial and temporal resolution. The nonintrusive and undisturbed gamma-ray attenuation method was applied in this study to establish a measuring scheme to detect the dynamic development of river bed clogging and to investigate the effects of fine sediments' particle-size distributions, total supplied mass, and supply rate on the sediment infiltration process. In a series of experiments, vertical profiles of infiltrated sediment masses were measured at two instants during the experiments. Then the dynamic changes of the infiltrated sediments at a specific position of the bed were investigated using continuous measurements during the experiments. The results of the measured vertical profile showed that sediment infiltration and clogging in an artificial bed matched the sediment's existing bridging criterion of the porous gravel bed. Furthermore, temporal changes occurred mainly in the upper layers. The continuous one-point measurements indicated almost real-time sediment accumulation development and proved that higher supply rates lead to an earlier start of the infiltration and rapid filling, whereas lower supply rates result in later and slower infiltration of the sediments. [ABSTRACT FROM AUTHOR]

Published
2022
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38. Oxidation-resistant gold-55 clusters. (Reports)

Author

Boyen, H.-G., Kastle, G., Weigl, F., Koslowski, B., Dietrich, C., Ziemann, P., Spatz, J.P., Riethmuller, S., Hartmann, C., Moller, M., Schmid, G., Garnier, M.G., and Oelhafen, P.

Subjects
Gold -- Composition -- Research, Nanotechnology -- Research, Oxidation-reduction reaction -- Research, Science and technology, Composition, Research
Abstract

Gold nanoparticles ranging in diameter from 1 to 8 nanometers were prepared on top of silicon wafers in order to study the size dependence of their oxidation behavior when exposed to atomic oxygen. X-ray photoelectron spectroscopy showed a maximum oxidation resistance for 'magic-number' clusters containing 55 gold atoms. This inertness is not related to electron confinement reading to a size-induced metal-to-insulator transition, but rather seems to be linked to the closed-shell structure of such magic dusters. The result additionally suggests that gold-55 clusters may act as especially effective oxidation catalysts, such as for oxidizing carbon monoxide., Bulk gold is oxidation-resistant in air even at elevated temperatures. Nonetheless, gold can react with oxygen. For example, [Au.sub.2][O.sub.3] can be prepared electrochemically (1) or by exposure to highly reactive [...]

Published
2002

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