TY - JOUR A1 - Lindner, G.-G. A1 - Hoffmann, Katrin A1 - Witke, Klaus A1 - Reinen, D. A1 - Heinemann, Chr. A1 - Koch, W. T1 - Spectroscopic Properties of Se2 2- and Se2- in Cancrinite KW - Selen KW - Cancrinit PY - 1996 SN - 0022-4596 SN - 1095-726X VL - 126 IS - 1 SP - 50 EP - 54 PB - Elsevier CY - San Diego, Calif. AN - OPUS4-690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drozdova, Y. A1 - Steudel, R. A1 - Hertwig, R. H. A1 - Koch, W. A1 - Steiger, Thomas T1 - Structures and Energies of Various Isomers of Dithionous Acid H2S2O4 and of Its Anion HS2O4 N2 - Ab initio molecular orbital calculations at various, correlated levels of theory have been performed on eight isomers of the [H,O4,S2]- anion and six forms of [H2,O4,S2]. For the former species, the hypothetical O3SSOH- (9) ion is identified as the lowest energy isomer using second-order Mller-Plesset perturbation theory or the CCSD(T) method, with the protonated dithionite ion, O2SSO2H- (6), being only marginally (less than 5 kJ mol-1 at 25 C) higher in energy. In contrast, the B3LYP density functional predicts a rather different order of relative stabilities, with O2SSO2H- (6) as the by far most stable ion. 6 is stable with respect to dissociation into SO2 and HOSO- or into SO2- and HOSO (which is more stable than HSO2). For the species of composition H2S2O4 the cagelike dithionous acid molecule (HO)O2SSO2(OH) (14) represents the global minimum at all four levels of theory. However, also for this species, the relative stabilities predicted by the B3LYP approach differ considerably from results obtained from the conventional wave function-based methods. 14 is stabilized by two very strong intramolecular hydrogen bonds (symmetry C2). The homolytic dissociation of 14 at the SS bond is strongly endothermic, but the molecule is unstable with respect to dissociation into H2SO2 and SO2. The harmonic wavenumbers and infrared intensities of the fundamental vibrations of 6 and 14 are given. PY - 1998 U6 - https://doi.org/10.1021/jp972658d SN - 1089-5639 SN - 1520-5215 VL - 102 IS - 6 SP - 990 EP - 996 PB - Soc. CY - Washington, DC AN - OPUS4-2587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schmidt, Birgit A1 - Koch, W. A1 - Pentzien, Simone A1 - Krüger, Jörg ED - Gabsch, T. T1 - Der Einsatz von Lasertechnik an Modellsystemen zentralasiatischer Wandmalereifragmente KW - Laserreinigung KW - Wandmalerei KW - Verrußung KW - Kunststoffschicht KW - Probekörper PY - 2012 SN - 978-3-7338-0385-8 IS - Kap. 10 SP - 152 EP - 157 PB - Koehler & Amelang GmbH AN - OPUS4-26178 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Birgit Angelika A1 - Ziemann, M. A A1 - Pentzien, Simone A1 - Gabsch, T. A1 - Koch, W. A1 - Krüger, Jörg T1 - Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road N2 - A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified. KW - Wall paintings KW - Central Asia KW - Silk Road KW - Pigments KW - Microscopy PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-357297 VL - 61 IS - 2 SP - 113 EP - 122 PB - Routledge Taylor & Francis Group CY - London AN - OPUS4-35729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -