TY - RPRT A1 - Göbel, E. O. A1 - Hasche, K. A1 - Ulm, G. A1 - Krumrey, M. A1 - Ade, G. A1 - Stümpel, J. A1 - Herrmann, K. A1 - Koenders, L. A1 - Thomsen-Schmidt, P. A1 - Pohlenz, F. A1 - Xu, M. A1 - Dai, G. A1 - Hoffmann, K.-P. A1 - Busch, I. A1 - Frank, W. A1 - Procop, M. A1 - Beck, Uwe T1 - Kalibrierte Schichtdicken-Maßverkörperungen für Nanometerschichten, Teilvorhaben - Kalibrierung von Schichtdicken-Maßverkörperungen im Nanometerbereich - Abschlussbericht des BMBF Verbundvorhabens 13N7704 - 13N77041 KW - Schichtdicke KW - Nanometerbereich PY - 2003 UR - http://edok01.tib.uni-hannover.de/edoks/e01fb02/373214030.pdf SP - 1 EP - 131 PB - Physikalisch-Technische Bundesanstalt CY - Dresden AN - OPUS4-25428 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bui, M. A1 - Hoffmann, K. F. A1 - Braun, T. A1 - Riedel, S. A1 - Heinekamp, Christian A1 - Scheurell, K. A1 - Scholz, G. A1 - Stawski, Tomasz A1 - Emmerling, Franziska T1 - An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis-Superacid for the Dehydrofluorination of Fluoroalkanes JF - ChemCatChem N2 - Ananion-dopedaluminiumchlorofluoride AlCl0.1F2.8(OTeF5)0.1(ACF-teflate) was synthesized.The material contains pentafluor-oorthotellurate(teflate)groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by73 cm-1, which is larger than the shift for SbF5. Remarkably,ACF-teflate catalyzes dehydrofluorination reactions of mono-fluoroalkanes to yield olefins in C6D6. In these cases,no Friedel-Crafts products were formed. KW - Aluminium fluorides KW - Aluminium teflates KW - C-F bond activation KW - Lewis superacids KW - Silanes PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572290 DO - https://doi.org/10.1002/cctc.202300350 SN - 1867-3880 SP - 1 EP - 7 PB - Wiley VHC-Verlag AN - OPUS4-57229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weh, K. A1 - Noack, M. A1 - Hoffmann, Katrin A1 - Schröder, K.-P. A1 - Caro, J. T1 - Change of gas permeation by photoinduced switching of zeolite-azobenzene membranes of type MFI and FAU JF - Microporous and mesoporous materials N2 - FAU membranes of type Na–X and MFI membranes of type silicalite-1 which contain adsorbed azobenzene (AZB), have photoswitchable permeation properties due to the trans–cis photoisomerization of AZB. The change of gas permeation through these host–guest composite membranes depends on the irradiation wavelength, the quality of the membranes and the amount of adsorbed AZB. The permeances of the gases in the trans-form of the zeolite-encapsulated AZB were higher than those in the cis-form. The separation factors of equimolar mixtures of N2/CO2 and CH4/CO2 fed through the FAU–AZB membrane were higher at trans-switching than at cis-switching. The changes of the permeances of single gases and of the separation factors of equimolar gas mixtures by photoinduced trans–cis switching were found to be reversible over numerous switching cycles. The experimental results are in agreement with predictions made by Monte Carlo simulations for passing of permeant gases through these host–guest systems with the zeolite-hosted AZB in the trans- and in the cis-configuration. PY - 2002 DO - https://doi.org/10.1016/S1387-1811(02)00331-1 SN - 1387-1811 SN - 1873-3093 VL - 54 IS - 1-2 SP - 15 EP - 26 PB - Elsevier CY - Amsterdam AN - OPUS4-1752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Hoffmann, V. A1 - Wetzig, K. A1 - Steers, E.B.M. T1 - Investigations of the effect of hydrogen in an argon glow discharge JF - Journal of analytical atomic spectrometry N2 - Clear evidence of the effects caused by hydrogen, introduced in different forms in an analytical glow discharge source (GDS) operated with argon, is presented for the different matrix elements copper, stainless steel, titanium, aluminium and silicon. When hydrogen is present even in small quantities in argon, not only are there significant changes in the emission line intensities of most elements (analyte and plasma species), but also new spectral features, such as emission bands of new compounds (hydrides of sputtered sample constituents) and a continuous background in the range ~220–440 nm. Moreover, the discharge current (the dependent parameter in our experiments) decreases with increasing hydrogen concentration. Different modes of hydrogen introduction, externally in gaseous form or sputtered as a sample constituent, cause very similar effects in terms of discharge current, line intensity (of analyte and plasma gas) and emission continua, which implies similar changes in the discharge processes in the two cases. The excitation of the hydrogen continuum appears to quench the population of the argon metastables (11.55 and 11.72 eV) and, consequently, other elementary processes in the plasma in which the argon metastables take part, but to a different extent for each analyte. PY - 2000 DO - https://doi.org/10.1039/b002367l SN - 0267-9477 SN - 1364-5544 IS - 15 SP - 1075 EP - 1080 PB - Royal Society of Chemistry CY - London AN - OPUS4-964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Hoffmann, V. A1 - Wetzig, K. A1 - Steers, E.B.M. T1 - Emission spectra of copper and argon in an argon glow discharge containing small quantities of hydrogen JF - Journal of analytical atomic spectrometry N2 - The influence of hydrogen contained in a sample or otherwise introduced into a glow discharge source (GDS) is here extensively experimentally presented for the case of copper as a sample by means of the addition of small quantities of molecular hydrogen (<1% relative partial pressure) to the argon carrier gas. The progressive addition of molecular hydrogen causes different intensity changes particular to the individual lines of different species such as atomic (Cu I) and ionic (Cu II) copper, and also atomic (Ar I) and ionic (Ar II) argon. Some interesting features of the emission spectrum of hydrogen such as its line, band and even continuum spectrum are observed. It was also found that the depth resolution becomes worse even at very low concentrations of hydrogen. PY - 2000 DO - https://doi.org/10.1039/b001565m SN - 0267-9477 SN - 1364-5544 IS - 15 SP - 951 EP - 958 PB - Royal Society of Chemistry CY - London AN - OPUS4-965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Hoffmann, V. A1 - Wetzig, K. A1 - Steers, E. T1 - ThP33 Investigations of the emission processes in argon glow discharges containing hydrogen JF - ICP information newsletter T2 - Winter Conference on Plasma Spectrochemistry 2000 CY - Fort Lauderdale, FL, USA DA - 2000-01-10 PY - 2000 SN - 0161-6951 VL - 25 SP - 1 EP - 2 PB - ICP Information Newsletter, Inc. CY - Amherst, Mass. AN - OPUS4-846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Steers, E.B.M. A1 - Hoffmann, V. A1 - Unger, Wolfgang A1 - Paatsch, Wolfgang A1 - Wetzig, K. T1 - Influence of hydrogen on the analytical figures of merit of glow discharge optical emission spectroscopy - friend or foe? JF - Journal of analytical atomic spectrometry PY - 2003 DO - https://doi.org/10.1039/b305384a SN - 0267-9477 SN - 1364-5544 VL - 18 SP - 521 EP - 526 PB - Royal Society of Chemistry CY - London AN - OPUS4-2290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wirth, Thomas A1 - Beck, Uwe A1 - Hoffmann, V. A1 - Kurt, R. A1 - Kämmer, K. A1 - Thielsch, R. T1 - Interference Phenomena at Transparent Layers in Glow Discharge Optical Emission Spectrometry JF - Applied spectroscopy KW - Glow discharge optical emission spectroscopy KW - Depth profile KW - Interference KW - Transparent layers KW - Layer thickness KW - Refractive index KW - GD-OES PY - 1999 SN - 0003-7028 SN - 1943-3530 VL - 53 IS - 8 SP - 987 EP - 990 PB - Society for Applied Spectroscopy CY - Frederick, Md. AN - OPUS4-777 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Hoffmann, V. A1 - Steers, E. B. M. A1 - Wetzig, K. T1 - Exploitation of the effect of hydrogen on an analytical glow discharge JF - ICP information newsletter T2 - Winter Conference on Plasma Spectrochemistry 2002 CY - Scottsdale, AZ, USA DA - 2002-01-06 PY - 2002 SN - 0161-6951 SP - 261 EP - 262 PB - ICP Information Newsletter, Inc. CY - Amherst, Mass. AN - OPUS4-1589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, V. A1 - Dorka, R. A1 - Wilken, L. A1 - Hodoroaba, Vasile-Dan A1 - Wetzig, K. T1 - Present possibilities of thin-layer analysis by GDOES JF - Surface and interface analysis N2 - The analysis of thin layers of thickness 100 nm has become a new field of application for glow discharge optical emission spectroscopy (GDOES). In this paper an overview is given of the experiences and possibilities gained by the authors in later years at their research, development and application of GDOES. During GDOES analysis of a multilayer system the depth resolution was determined using the inverse maximal slope method. Under optimized discharge conditions a depth resolution of 25 nm at 100 nm depth was achieved. The gas flow in a Grimm-type source for glow discharge mass spectrometry (GDMS) was simulated and a correlation between calculated pressure and crater shape was found. Cleanness of the sample and source turned out to be essential for a fast stabilization time and reduction of the influence of light elements and molecules. Thereby, a 10 nm layer at the top surface of a sample could be quantified. Apart from the influence of density, the reflectivity of the sample surface is discussed. It is shown that a high sample reflectivity can cause up to 100% more light to be measured by the spectrometer. KW - GDOES KW - GDMS KW - Thin-layer analysis PY - 2003 DO - https://doi.org/10.1002/sia.1575 SN - 0142-2421 SN - 1096-9918 VL - 35 IS - 7 SP - 575 EP - 582 PB - Wiley CY - Chichester AN - OPUS4-2624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -