Search results for "ddc:54"
showing 10 items of 218 documents
Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C(22)C(1)im](+)[NTf2](-)
2017
Physical chemistry, chemical physics 19(39), 26651 - 26661 (2017). doi:10.1039/C7CP04852A
Diffusion of single molecular and macromolecular probes during the free radical bulk polymerization of MMA : towards a better understanding of the Tr…
2016
Free radical bulk polymerizations exhibit complex kinetics due to the viscosity increase during the polymerization process. Especially the termination rate constant can be strongly influenced by the mobility of polymer chains in the polymerization mixture. As a consequence an autoacceleration period, the so-called Trommsdorff effect, can be observed often. In order to investigate this behaviour on a nanoscopic scale, we directly visualized the mobility of molecules and macromolecules in polymerizing MMA solutions using a combination of highly sensitive fluorescence correlation spectroscopy and widefield fluorescence microscopy. For this purpose, rather monodisperse PMMA chains were synthesi…
Monolayers of rod-shaped and disc-shaped liquid crystalline compounds at the air-water interface
2008
Calamitic (rod-shaped) and discotic (disc-shaped) thermotropic liquid crystalline (LC) compounds were spread at the air-water interface, and their ability to form monolayers was studied. The calamitic LCs investigated were found to form monolayers which behave analogously to conventional amphiphiles such as fatty acids. The spreading of the discotic LCs produced monolayers as well, but with a behaviour different from classical amphiphiles. The areas occupied per molecule are too small to allow the contact of all hydrophilic groups with the water surface and the packing of all hydrophobic chains. Various molecular arrangements of the discotics at the water surface to fit the spreading data a…
Relaxation and charge transport in mixtures of zwitterionic polymers and inorganic salts
2009
Dielectric spectroscopy is employed to analyze the molecular dynamics and the charge transport in mixtures of zwitterionic polymers of the type poly(3-[N-(omega-methacryloyloxyalkyl)-N, N-dimethylammonio]propanesulfonate) with sodium iodide in the frequency range of 10(2) Hz-10(7) Hz and in the temperature range of 110 K-400 K. The amount of inorganic salt added varies from 0-200 mol-% relative to the number of zwitterionic groups present in the polymer, contributing strongly to the conductivity. One relaxation process is observed whose relaxation rate depends strongly on the length of the aliphatic spacer between the polymethacrylate main chain and the zwitterionic group. Exhibiting an Arr…
Efficient size control of copper nanoparticles generated in irradiated aqueous solutions of star-shaped polyelectrolyte containers
2015
Physical chemistry, chemical physics 17(17), 11490-11498(2015). doi:10.1039/C5CP00269A
Five-Membered 2-Methylene-2,3-dihydro Heterocycles from Ruthenium Butatrienylidene Intermediates and 2-(Dimethylamino)methyl-Substituted Furans, Thio…
2003
Trapping of the primary butatrienylidene intermediate trans-[Cl(dppm) 2 Ru=C=C=C=CH 2 ] + with five-membered 2-(dimethylamino)methyl-substituted heterocycles provides an easy and efficient route to aminoallenylidene complexes with appended 2-methylene-2,3-dihydrofuran, -thiophene, or -selenophene moieties. Upon warming or acid catalysis isomerization to the aromatic 2-methylated isomers is observed.
Characterization of the atmospheric muon flux in IceCube
2015
Muons produced in atmospheric cosmic ray showers account for the by far dominant part of the event yield in large-volume underground particle detectors. The IceCube detector, with an instrumented volume of about a cubic kilometer, has the potential to conduct unique investigations on atmospheric muons by exploiting the large collection area and the possibility to track particles over a long distance. Through detailed reconstruction of energy deposition along the tracks, the characteristics of muon bundles can be quantified, and individual particles of exceptionally high energy identified. The data can then be used to constrain the cosmic ray primary flux and the contribution to atmospheric …
Prediction of new inorganic molecules with quantum chemical methods
2006
Quantum chemistry can today be employed to invent new molecules and explore unknown molecular bonding. An overview of novel species containing metals bound to polynitrogen clusters is presented. The prediction of metal polyhydrides is discussed. Finally, some species containing gold that behaves as a halogen are described, together with recent advances in actinide chemistry and exploration of the nature of the actinide–actinide chemical bonding.
Quantum Chemical Calculations Predict the Diphenyl Diuranium Compound [PhUUPh] To Have a Stable1Ag Ground State
2006
Study of the MAu6(M = Cr, Mo, W) molecular species: A transition from halogenlike to hydrogenlike chemical behavior for gold
2004
Quantum chemical calculations suggest that a series of molecules with the general formula MAu6 are stable, where M is a a group 6 atom, Cr, Mo, W, respectively. These species have a structure analogous to the corresponding MH6 compounds, while they differ from the MX6, where X is a halogen. The further reaction MAu6 + 3Au2 → MAu12 is strongly exothermic.