@article{38013, author = {{Christoffers, Jens and Kauf, Thomas and Werner, Thomas and Rössle, Michael}}, issn = {{1434-193X}}, journal = {{European Journal of Organic Chemistry}}, keywords = {{Organic Chemistry, Physical and Theoretical Chemistry}}, number = {{11}}, pages = {{2601--2608}}, publisher = {{Wiley}}, title = {{{Cerium-Catalyzed α-Hydroxylation Reactions of α-Cyclopropyl β-Dicarbonyl Compounds with Molecular Oxygen}}}, doi = {{10.1002/ejoc.200600061}}, volume = {{2006}}, year = {{2006}}, } @article{38012, author = {{Werner, Thomas and Barrett, Anthony G. M.}}, issn = {{0022-3263}}, journal = {{The Journal of Organic Chemistry}}, keywords = {{Organic Chemistry}}, number = {{11}}, pages = {{4302--4304}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Simple Method for the Preparation of Esters from Grignard Reagents and Alkyl 1-Imidazolecarboxylates}}}, doi = {{10.1021/jo060562m}}, volume = {{71}}, year = {{2006}}, } @article{39761, author = {{Paelke, Lutz and Kitzerow, Heinz-Siegfried}}, issn = {{0021-8979}}, journal = {{Journal of Applied Physics}}, keywords = {{General Physics and Astronomy}}, number = {{11}}, publisher = {{AIP Publishing}}, title = {{{Space charge field and dynamics of the grating formation in a photorefractive polymer-dispersed liquid crystal based on a photoconducting polysiloxane}}}, doi = {{10.1063/1.2372434}}, volume = {{100}}, year = {{2006}}, } @article{41286, author = {{Bauer, Matthias and Gastl, Christoph and Köppl, Christoph and Kickelbick, Guido and Bertagnolli, Helmut}}, issn = {{0026-9247}}, journal = {{Monatshefte für Chemie - Chemical Monthly}}, keywords = {{General Chemistry}}, number = {{5}}, pages = {{567--581}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{EXAFS Spectroscopy of the Alkoxide Precursor Zr(OnBu)4 and its Modification in Solution}}}, doi = {{10.1007/s00706-006-0450-z}}, volume = {{137}}, year = {{2006}}, } @article{41285, author = {{Supplit, R. and Hüsing, N. and Bertagnolli, H. and Bauer, Matthias and Kessler, V. and Seisenbaeva, G. A. and Bernstorff, S. and Gross, S.}}, issn = {{0959-9428}}, journal = {{J. Mater. Chem.}}, keywords = {{Materials Chemistry, General Chemistry}}, number = {{45}}, pages = {{4443--4453}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Synthesis and characterization of orthorhombic, 2d-centered rectangular and lamellar iron oxide doped silica films}}}, doi = {{10.1039/b606386a}}, volume = {{16}}, year = {{2006}}, } @article{41284, author = {{Liu, Xiong and Bauer, Matthias and Bertagnolli, Helmut and Roduner, Emil and van Slageren, Joris and Phillipp, Fritz}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, keywords = {{General Physics and Astronomy}}, number = {{25}}, publisher = {{American Physical Society (APS)}}, title = {{{Structure and Magnetization of Small Monodisperse Platinum Clusters}}}, doi = {{10.1103/physrevlett.97.253401}}, volume = {{97}}, year = {{2006}}, } @article{31754, author = {{Felleiter, P and Reinsberger, Claus and Springe, D and Plunien, H and Baumberger, M}}, issn = {{0939-2661}}, journal = {{Anasthesiol Intensivmed Notfallmed Schmerzther}}, number = {{1}}, pages = {{9--13}}, title = {{{Preclinical diagnosis of traumatic paraplegia or tetraplegia - a prospective study in 100 patients.}}}, volume = {{41}}, year = {{2006}}, } @article{42008, author = {{Schweins, R. and Goerigk, G. and Huber, Klaus}}, issn = {{1292-8941}}, journal = {{The European Physical Journal E}}, keywords = {{Surfaces and Interfaces, General Materials Science, General Chemistry, Biophysics, Biotechnology}}, number = {{2}}, pages = {{99--110}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Shrinking of anionic polyacrylate coils induced by Ca2+, Sr2+ and Ba2+: A combined light scattering and ASAXS study}}}, doi = {{10.1140/epje/i2006-10047-7}}, volume = {{21}}, year = {{2006}}, } @article{25993, abstract = {{The growth of ZnS nanoparticles by precipitation from supersaturated aqueous solution is studied by stopped-flow UV absorption spectroscopy. The average size, size distribution, and concentration of the particles are monitored within the sub-second time regime with a resolution of 1.28 ms. Particle growth at these early stages is governed by pronounced ripening. The UV absorption data strongly suggest that growth occurs by preferential adsorption of HS- anions relative to Zn2+ or ZnOH+ cations. Correspondingly, the initial sulfide concentration has a much more pronounced influence on the growth kinetics than the initial zinc concentration. These findings are verified by ζ-potential measurements which confirm that the particle surfaces are negatively charged under near-neutral pH conditions.}}, author = {{Tiemann, Michael and Marlow, Frank and Brieler, Felix and Lindén, Mika}}, issn = {{1520-6106}}, journal = {{The Journal of Physical Chemistry B}}, pages = {{23142--23147}}, title = {{{Early Stages of ZnS Growth Studied by Stopped-Flow UV Absorption Spectroscopy:  Effects of Educt Concentrations on the Nanoparticle Formation}}}, doi = {{10.1021/jp0638383}}, year = {{2006}}, } @article{25992, abstract = {{We report on the synthesis and CO gas-sensing properties of mesoporous tin(IV) oxides (SnO2). For the synthesis cetyltrimethylammonium bromide (CTABr) was used as a structure-directing agent; the resulting SnO2 powders were applied as films to commercially available sensor substrates by drop coating. Nitrogen physisorption shows specific surface areas up to 160 m2·g-1 and mean pore diameters of about 4 nm, as verified by TEM. The film conductance was measured in dependence on the CO concentration in humid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivity at low CO concentrations and turn out to be largely insensitive towards changes in the relative humidity. We compare the materials with commercially available SnO2-based sensors.}}, author = {{Wagner, Thorsten and Kohl, Claus-Dieter and Fröba, Michael and Tiemann, Michael}}, issn = {{1424-8220}}, journal = {{Sensors}}, pages = {{318--323}}, title = {{{Gas Sensing Properties of Ordered Mesoporous SnO2}}}, doi = {{10.3390/s6040318}}, year = {{2006}}, } @article{25991, abstract = {{Periodically ordered mesoporous magnesium oxide was synthesized in a double replication procedure. Mesoporous SBA-15 silica and CMK-3 carbon were successively used as hard structure matrixes. The carbon pore system was infiltrated with Mg(NO3)2, which was then converted to MgO at 573 K; the carbon matrix was finally removed by thermal combustion. The structure of the mesoporous MgO corresponds to that of the original SBA-15 silica. The products consist of hexagonally arranged cylindrical mesopores and crystalline pore walls. The efficiency of the replication series was studied by variation of the infiltration method and comprehensive pore size analysis of all involved mesoporous materials. The in situ formation of MgO inside the CMK-3 carbon pore system was monitored by thermal analysis. Postsynthetic treatment of the products at 823 K in a vacuum prior to removal of the carbon matrix was found to improve the crystallinity but to diminish the periodic order of the pore system.}}, author = {{Roggenbuck, Jan and Koch, Günter and Tiemann, Michael}}, issn = {{0897-4756}}, journal = {{Chemistry of Materials}}, pages = {{4151--4156}}, title = {{{Synthesis of Mesoporous Magnesium Oxide by CMK-3 Carbon Structure Replication}}}, doi = {{10.1021/cm060740s}}, year = {{2006}}, } @inbook{43269, abstract = {{The derivation of a microscopic many-body theory for the nonlinear optical response of semiconductors is reviewed. At the Hartree–Fock level, the semiconductor Bloch equations include many-body effects via band gap and field renormalization. These equations are sufficient to describe excitonic resonances as they appear already in the linear absorption spectra. An adequate description of nonlinear optical effects in semiconductors beyond the Hartree–Fock level includes Coulomb interaction induced carrier correlations. Different schemes have been developed to treat such correlation effects. As two examples, the second-order Born approximation and the dynamics-controlled truncation scheme are introduced and analyzed. In addition to the derivation of the equations of motion, a few examples are presented which highlight important signatures of many-body correlations in the optical response of semiconductors.}}, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Quantum Coherence: From Quarks to Solids}}, isbn = {{978-3-540-30085-4}}, pages = {{115--152}}, publisher = {{Springer, Berlin, Heidelberg}}, title = {{{Microscopic Theory of Coherent Semiconductor Optics}}}, doi = {{10.1007/11398448_4}}, volume = {{689}}, year = {{2006}}, } @article{23493, abstract = {{A microscopic analysis is presented for the extreme nonlinear optical response of semiconductor quantum wells and wires after intense excitation with femtosecond laser pulses. In this regime, the light–matter interaction is the dominant eneregy scale, leading to a number of interesting effects such as carrier-wave Rabi flopping, Mollow splitting, and the creation of higher harmonics. The results presented here were obtained by evaluating the semiconductor Bloch equations without the rotating wave approximation. The electronic dispersion of semiconductor nanostructures is shown to have a characteristic influence on the extreme nonlinear optical response, whereas the relative importance of the carrier Coulomb interaction decreases with increasing excitation intensities.}}, author = {{Golde, Daniel and Meier, Torsten and Koch, Stephan W.}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, number = {{12}}, pages = {{2559--2565}}, title = {{{Microscopic analysis of extreme nonlinear optics in semiconductor nanostructures}}}, doi = {{10.1364/josab.23.002559}}, volume = {{23}}, year = {{2006}}, } @article{23495, abstract = {{The method of angular photonic correlations of spontaneous emission is introduced as an experimental, purely optical scheme to characterize disorder in semiconductor nanostructures. The theoretical expression for the angular correlations is derived and numerically evaluated for a model system. The results demonstrate how the proposed experimental method yields direct information about the spatial distribution of the relevant states and thus on the disorder present in the system.}}, author = {{Bozsoki, P. and Thomas, P. and Kira, M. and Hoyer, W. and Meier, Torsten and Koch, S. W. and Maschke, K. and Varga, I. and Stolz, H.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{22}}, title = {{{Characterization of Disorder in Semiconductors via Single-Photon Interferometry}}}, doi = {{10.1103/physrevlett.97.227402}}, volume = {{97}}, year = {{2006}}, } @inproceedings{43265, abstract = {{The dynamics of charge and spin currents generated by two-color femtosecond laser pulses is investigated. Non-Markovian memory effects lead to oscillations in the coherent transients. Consequences arising from the heavy-hole light-hole coupling are predicted.}}, author = {{Meier, Torsten and Vu, Q.T. and Duc, H.T. and Pasenow, B. and Haug, H. and Koch, S.W.}}, booktitle = {{International Conference on Ultrafast Phenomena XV}}, isbn = {{1-55752-810-1}}, location = {{Pacific Grove, California United States}}, publisher = {{Optical Society of America}}, title = {{{Microscopic Many-Body Analysis of Ultrafast Photocurrents in Semiconductor Nanostructures}}}, doi = {{10.1364/UP.2006.TuD8}}, volume = {{88}}, year = {{2006}}, } @article{23491, abstract = {{A brief overview of a consistent microscopic approach to model the optical and electronic properties of semiconductor nanostructures is presented. Coupled semiconductor Bloch and Maxwell equations are used to investigate the performance of semiconductor microcavity structures, photonic band gap systems, and lasers. The predictive potential of the microscopic theory is demonstrated for several examples of practical importance. Optical gain and output characteristics are computed for modern vertical external cavity surface emitting laser structures. It is shown how design flexibilities can be used to optimize the device performance. Nanostructures are proposed where semiconductor quantum wells are embedded in one-dimensional photonic crystals. For field modes spectrally below the photonic band edge it is shown that the optical gain and absorption can be enhanced by more than one order of magnitude over the value of the homogeneous medium. The increased gain can be used for laser action by placing quantum wells and a suitably designed photonic crystal structure inside a microcavity.}}, author = {{Thränhardt, A. and Meier, Torsten and Reichelt, Matthias and Schlichenmaier, C. and Pasenow, B. and Kuznetsova, I. and Becker, S. and Stroucken, T. and Hader, J. and Zakharian, A.R. and Moloney, J.V. and Chow, W.W. and Koch, S.W.}}, issn = {{0022-3093}}, journal = {{Journal of Non-Crystalline Solids}}, number = {{23-25}}, pages = {{2480--2483}}, title = {{{Microscopic modeling of the optical properties of semiconductor nanostructures}}}, doi = {{10.1016/j.jnoncrysol.2006.02.064}}, volume = {{352}}, year = {{2006}}, } @article{23492, abstract = {{The coherent ultrafast optical injection and the temporal evolution of charge and spin currents in semiconductors is analyzed using a microscopic many-body theory. The approach is based on the semiconductor Bloch equations and includes light-field-induced intraband and interband excitations, excitonic effects, and carrier–LO-phonon and carrier-carrier scattering processes. The relaxation effects are treated both in the second Born-Markov approximation and on the level of quantum kinetic theory including memory effects. The dynamics of the charge and spin currents is evaluated numerically for a one-dimensional model system. The dependence of the currents and their decay on the temperature, the excitation intensities, and the frequencies of the incident light fields is discussed. Whereas the overall decay dynamics is described well within the Markov approximation, the quantum kinetic theory predicts additional oscillatory signatures in the current transients.}}, author = {{Duc, H. T. and Vu, Q. T. and Meier, Torsten and Haug, H. and Koch, S. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{16}}, title = {{{Temporal decay of coherently optically injected charge and spin currents due to carrier–LO-phonon and carrier-carrier scattering}}}, doi = {{10.1103/physrevb.74.165328}}, volume = {{74}}, year = {{2006}}, } @inbook{44120, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Photonic Crystals: Advances in Design, Fabrication, and Characterization}}, editor = {{Busch, Kurt and Lölkes, Stefan and Wehrspohn, Ralf B. and Föll, Helmut}}, pages = {{43--62}}, publisher = {{John Wiley & Sons}}, title = {{{Semiconductor Optics in Photonic Crystal Structures}}}, year = {{2006}}, } @inbook{43270, abstract = {{The linear and nonlinear optical properties of semiconductors are strongly influenced by the Coulomb interaction among the photoexcited carriers. Within the framework of the semiconductor Bloch equations such many-body effects can be described on the basis of a microscopic theory. In this article, we briefly review our recent contributions to two specific topics. First, the coherent optical generation of charge and spin currents and their subsequent decay via scattering processes is discussed. As a second example, the spatially-inhomogeneous optical properties of hybrid structures which consist of photonic crystals and semiconductor nanostructures are described. Many of the numerical results have been obtained using massively parallel computer programs which were run on the IBM p690-Cluster Jump in Jülich.}}, author = {{Meier, Torsten and Duc, Huynh Thanh and Reichelt, Matthias and Pasenow, B. and Stroucken, T. and Koch, S.W.}}, booktitle = {{Germany in NIC Series Vol. 32}}, editor = {{Munster, G. and Wolf, D. and Kremer, M.}}, isbn = {{3-00-017351-X}}, pages = {{219--226}}, publisher = {{John von Neumann Institute for Computing}}, title = {{{Computational Optoelectronics of Semiconductor Nanostructures including Many-Body Effects}}}, year = {{2006}}, } @inproceedings{44294, abstract = {{The band alignment of GaNAs in heterostructures is determined by investigating the energetically lowest optical band-to-band transition of In0.23Ga0.77As/GaNyAs1−y samples with varying y. In a type II alignment this transition is between states located in different layers. Photoreflectance, photoluminescence, and the radiative decay of excited carrier densities are both measured and microscopically modeled. The bandstructure for every sample is computed. Based on this bandstructure all optical properties and the radiative decay are computed using the semiconductor Bloch [1] and luminescence [2] equations including electron-electron and electron-phonon interaction on scattering level. Thus the modeling is consistent and without free parameters. Overall good agreement between theory and experiment is achieved and used to explain all experimental features and to determine the band alignment}}, author = {{Meier, Torsten and Schlichenmaier, C. and Thraenhardt, Angela and Koch, S.W. and Hantke, Kristian and Ruehle, Wolfgang and Gruening, Heiko and Klar, Peter J. and Heimbrodt, Wolfgang and Hader, J. and Moloney, Jerome V.}}, booktitle = {{Meeting of the German Physical Society, Solid-State Physics Section, and the European Physical Society Condensed Matter Division}}, location = {{ Dresden, Germany}}, title = {{{Type I type II transition in optical spectra-experiments and microscopic theory}}}, volume = {{41}}, year = {{2006}}, }