@article{HegewaldSchmidtGohsetal.2005, author = {Hegewald, J. and Schmidt, T. and Gohs, U. and Gunther, M. and Reichelt, R. and Stiller, Burkhard and Arndt, K. F.}, title = {Electron beam irradiation of poly(vinyl methyl ether) films : 1. Synthesis and film topography}, issn = {0743-7463}, year = {2005}, abstract = {Temperature-sensitive hydrogel layers on silicon (Si) substrates were synthesized by electron beam irradiation of spin-coated poly(vinyl methyl ether) (PVME) films. The influences of the used solvent, the polymer concentration, and the spinning velocity on the homogeneity and the thickness of the PVME film were investigated. In the range of concentration c(p) = 1-15 wt\% PVME in ethanol solution, homogeneous films with a thickness between d = 50 nm and 1.7 mu m were obtained. The films were cross-linked by electron beam irradiation under inert atmosphere and analyzed by sol-gel- analysis. The results were compared with bulkgels formed by electron beam irradiation of PVME in the dry state. The film topography was analyzed by high-resolution field emission scanning electron microscopy and atomic force microscopy. An islandlike structure in the dry, swollen, and shrunken state of the hydrogel films was observed}, language = {en} } @article{SchmidtLorenz2016, author = {Schmidt, Burkhard and Lorenz, Ulf}, title = {WavePacket}, series = {Computer physics communications : an international journal devoted to computational physics and computer programs in physics}, volume = {213}, journal = {Computer physics communications : an international journal devoted to computational physics and computer programs in physics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0010-4655}, doi = {10.1016/j.cpc.2016.12.007}, pages = {223 -- 234}, year = {2016}, abstract = {WavePacket is an open-source program package for the numerical simulation of quantum-mechanical dynamics. It can be used to solve time-independent or time-dependent linear Schr{\"o}dinger and Liouville-von Neumann-equations in one or more dimensions. Also coupled equations can be treated, which allows to simulate molecular quantum dynamics beyond the Born-Oppenheimer approximation. Optionally accounting for the interaction with external electric fields within the semiclassical dipole approximation, WavePacket can be used to simulate experiments involving tailored light pulses in photo-induced physics or chemistry. The graphical capabilities allow visualization of quantum dynamics 'on the fly', including Wigner phase space representations. Being easy to use and highly versatile, WavePacket is well suited for the teaching of quantum mechanics as well as for research projects in atomic, molecular and optical physics or in physical or theoretical chemistry. The present Part I deals with the description of closed quantum systems in terms of Schr{\"o}dinger equations. The emphasis is on discrete variable representations for spatial discretization as well as various techniques for temporal discretization. The upcoming Part II will focus on open quantum systems and dimension reduction; it also describes the codes for optimal control of quantum dynamics. The present work introduces the MATLAB version of WavePacket 5.2.1 which is hosted at the Sourceforge platform, where extensive Wiki-documentation as well as worked-out demonstration examples can be found.}, language = {en} } @article{BernhardMoskwaSchmidtetal.2018, author = {Bernhard, Nadine and Moskwa, Lisa-Marie and Schmidt, Karsten and Oeser, Ralf Andreas and Aburto, Felipe and Bader, Maaike Y. and Baumann, Karen and von Blanckenburg, Friedhelm and Boy, Jens and van den Brink, Liesbeth and Brucker, Emanuel and Buedel, Burkhard and Canessa, Rafaella and Dippold, Michaela A. and Ehlers, Todd and Fuentes, Juan P. and Godoy, Roberto and Jung, Patrick and Karsten, Ulf and Koester, Moritz and Kuzyakov, Yakov and Leinweber, Peter and Neidhardt, Harald and Matus, Francisco and Mueller, Carsten W. and Oelmann, Yvonne and Oses, Romulo and Osses, Pablo and Paulino, Leandro and Samolov, Elena and Schaller, Mirjam and Schmid, Manuel and Spielvogel, Sandra and Spohn, Marie and Stock, Svenja and Stroncik, Nicole and Tielboerger, Katja and Uebernickel, Kirstin and Scholten, Thomas and Seguel, Oscar and Wagner, Dirk and K{\"u}hn, Peter}, title = {Pedogenic and microbial interrelations to regional climate and local topography}, series = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution}, volume = {170}, journal = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0341-8162}, doi = {10.1016/j.catena.2018.06.018}, pages = {335 -- 355}, year = {2018}, abstract = {The effects of climate and topography on soil physico-chemical and microbial parameters were studied along an extensive latitudinal climate gradient in the Coastal Cordillera of Chile (26 degrees-38 degrees S). The study sites encompass arid (Pan de Azucar), semiarid (Santa Gracia), mediterranean (La Campana) and humid (Nahuelbuta) climates and vegetation, ranging from arid desert, dominated by biological soil crusts (biocrusts), semiarid shrubland and mediterranean sclerophyllous forest, where biocrusts are present but do have a seasonal pattern to temperate-mixed forest, where biocrusts only occur as an early pioneering development stage after disturbance. All soils originate from granitic parent materials and show very strong differences in pedogenesis intensity and soil depth. Most of the investigated physical, chemical and microbiological soil properties showed distinct trends along the climate gradient. Further, abrupt changes between the arid northernmost study site and the other semi-arid to humid sites can be shown, which indicate non-linearity and thresholds along the climate gradient. Clay and total organic carbon contents (TOC) as well as Ah horizons and solum depths increased from arid to humid climates, whereas bulk density (BD), pH values and base saturation (BS) decreased. These properties demonstrate the accumulation of organic matter, clay formation and element leaching as key-pedogenic processes with increasing humidity. However, the soils in the northern arid climate do not follow this overall latitudinal trend, because texture and BD are largely controlled by aeolian input of dust and sea salts spray followed by the formation of secondary evaporate minerals. Total soil DNA concentrations and TOC increased from arid to humid sites, while areal coverage by biocrusts exhibited an opposite trend. Relative bacterial and archaeal abundances were lower in the arid site, but for the other sites the local variability exceeds the variability along the climate gradient. Differences in soil properties between topographic positions were most pronounced at the study sites with the mediterranean and humid climate, whereas microbial abundances were independent on topography across all study sites. In general, the regional climate is the strongest controlling factor for pedogenesis and microbial parameters in soils developed from the same parent material. Topographic position along individual slopes of limited length augmented this effect only under humid conditions, where water erosion likely relocated particles and elements downward. The change from alkaline to neutral soil pH between the arid and the semi-arid site coincided with qualitative differences in soil formation as well as microbial habitats. This also reflects non-linear relationships of pedogenic and microbial processes in soils depending on climate with a sharp threshold between arid and semi-arid conditions. Therefore, the soils on the transition between arid and semi-arid conditions are especially sensitive and may be well used as indicators of long and medium-term climate changes. Concluding, the unique latitudinal precipitation gradient in the Coastal Cordillera of Chile is predestined to investigate the effects of the main soil forming factor - climate - on pedogenic processes.}, language = {en} } @article{SpallanzaniKogaCichyetal.2022, author = {Spallanzani, Roberta and Koga, Kenneth T. and Cichy, Sarah B. and Wiedenbeck, Michael and Schmidt, Burkhard C. and Oelze, Marcus and Wilke, Max}, title = {Lithium and boron diffusivity and isotopic fractionation in hydrated rhyolitic melts}, series = {Contributions to mineralogy and petrology}, volume = {177}, journal = {Contributions to mineralogy and petrology}, number = {8}, publisher = {Springer}, address = {New York}, issn = {0010-7999}, doi = {10.1007/s00410-022-01937-2}, pages = {17}, year = {2022}, abstract = {Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the diffusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt\% water), having different Li and B contents; these were studied in diffusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700-1250 degrees C for durations from 0 s to 24 h. From this we determined activation energies for Li and B diffusion of 57 +/- 4 kJ/mol and 152 +/- 15 kJ/mol with pre-exponential factors of 1.53 x 10(-7) m(2)/s and 3.80 x 10(-8) m(2)/s, respectively. Lithium isotopic fractionation during diffusion gave beta values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li diffusivities and isotopic fractionation results differ somewhat from earlier published values, but overall confirm that Li diffusivity increases with water content. Our results on B diffusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confirm that B diffusivity is limited by viscous flow in silicate melts. Our results on Li and B diffusion present a new tool for understanding degassing-related processes, offering a potential geospeedometer to measure volcanic ascent rates.}, language = {en} }