@article{MikatFrancoRegensteinetal.2000,
  author    = {Mikat, J{\"u}rgen E. R. and Franco, Olga and Regenstein, Wolfgang and Reck, G{\"u}nter and Knochenhauer, Gerald and Schulz, Burkhard and Orgzall, Ingo},
  title     = {1,3,4-oxadiazole crystals under high pressure-phase transitions and properties},
  year      = {2000},
  language  = {en}
}
@article{ReicheKnochenhauer1994,
  author    = {Reiche, J{\"u}rgen and Knochenhauer, Gerald},
  title     = {Numerische Simulation und R{\"o}ntgenbeugung an thermisch aufgedampften Multischichten perfluorierter Fetts{\"a}uren},
  year      = {1994},
  language  = {de}
}
@article{OrgzallLorenzMikatetal.1997,
  author    = {Orgzall, Ingo and Lorenz, Bernd and Mikat, J{\"u}rgen E. R. and Dietel, Reinhard and Knochenhauer, Gerald and Schulz, Burkhard},
  title     = {Raman and IR spectroscopic investigation of aromatic 1,3,4-oxadiazole polymers and oligomers},
  year      = {1997},
  abstract  = {The molecular structure of poly(p-phenylene-1,3,4-oxadiazole) (POD) is investigated using i.r. and Raman spectroscopy. Both methods reveal characteristic differences for the a- and b-POD forms that are most obvious in the spectral region between 1500 and 1650 cm-1. The spectra for dimer and tetramer compounds already show the same features as found for longer chains. Based on molecular modelling calculations these differences are assigned to cis and trans conformations of the main chain segments. High pressure measurements show a linear shift of the Raman lines and support the result of the thermodynamic stability of the trans conformation.},
  language  = {en}
}
@article{SchulzStillerZetzscheetal.1997,
  author    = {Schulz, Burkhard and Stiller, Burkhard and Zetzsche, Thomas and Knochenhauer, Gerald and Brehmer, Ludwig},
  title     = {Characterization of crystals based on 1,3,4-oxadiazoles by atomic force microscopy},
  year      = {1997},
  abstract  = {The surface structures of crystals based on aromatic oxadiazoles were investigated by AFM. The crystal structure for 2,5-di(p-tolyl)-1,3,4-oxadiazole (DTO) differs from that of 2,5-di (4-methoxycarbonyl-phenyl)-1,3,4- oxadiazole (DMPO). In DMPO all molecules show parallel orientation to the surface in such a way that the surface is formed as well as by the nitrogen atoms of the heterocyclic rings and the methyl groups of the ester substituents. By contrast, the oxadiazole molecules in DTO crystals are oriented perpendicular to the crystal surface. The experimental data are interpreted by molecular modelling. It is shown that there is a difference between molecular structure of the surface, as detected by AFM, and the bulk structure determined by X-ray diffraction.},
  language  = {en}
}
@article{ReicheZetzscheHelmsetal.1997,
  author    = {Reiche, J{\"u}rgen and Zetzsche, Thomas and Helms, Andreas and Freydank, Anke-Christine and Knochenhauer, Gerald and Schulz, Burkhard and Brehmer, Ludwig},
  title     = {Organized molecular films of oxadiazole compounds formed by vacuum deposition},
  year      = {1997},
  language  = {en}
}
@article{ReicheFreydankDietzeletal.1995,
  author    = {Reiche, J{\"u}rgen and Freydank, A. and Dietzel, Birgit and Katholy, Stefan and Knochenhauer, Gerald and Zetzsche, Thomas and Schulz, Burkhard and Brehmer, Ludwig},
  title     = {Komplexe Strukturanalytik von Oxadiazol-Mono- und Multischichten},
  year      = {1995},
  language  = {de}
}
@article{BrehmerDietzelFreydanketal.1995,
  author    = {Brehmer, Ludwig and Dietzel, Birgit and Freydank, Anke-Christine and Katholy, Stefan and Knochenhauer, Gerald and Reiche, J{\"u}rgen and Schulz, Burkhard and Zetzsche, Thomas},
  title     = {Langmuir- und Langmuir-Blodgett-Filme amphiphiler Oxadiazole},
  year      = {1995},
  language  = {de}
}
@article{OrgzallLorenzMikatetal.1998,
  author    = {Orgzall, Ingo and Lorenz, Bernd and Mikat, J{\"u}rgen E. R. and Reck, G{\"u}nter and Knochenhauer, Gerald and Schulz, Burkhard},
  title     = {Phase transition in 1,3,4-oxadiazole crystals under high pressure},
  year      = {1998},
  language  = {en}
}
@article{ReicheKnochenhauerBarberkaetal.1995,
  author    = {Reiche, J{\"u}rgen and Knochenhauer, Gerald and Barberka, Thomas Andreas and Geue, Thomas and Pietsch, Ullrich and Brehmer, Ludwig and Hodge, P. and Tredgold, Richard H.},
  title     = {In-plane structure of perfluorotetra decanoic acid Langmuir-Blodgett films and films formed by vacuum deposition},
  year      = {1995},
  language  = {en}
}
@article{SchulzKnochenhauerBrehmeretal.1995,
  author    = {Schulz, Burkhard and Knochenhauer, Gerald and Brehmer, Ludwig and Janietz, Silvia},
  title     = {Stuctures and properties of aromatic poly(1,3,4-oxadiazole)s},
  year      = {1995},
  language  = {en}
}
@article{SchulzStillerZetzscheetal.1995,
  author    = {Schulz, Burkhard and Stiller, Burkhard and Zetzsche, Thomas and Knochenhauer, Gerald and Dietel, Reinhard and Brehmer, Ludwig},
  title     = {Characterization of 2,5-di(p-tolyl-1,3,4- oxadiazole) crystals by IR-spectroscopy and atomic force microscopy},
  year      = {1995},
  language  = {en}
}
@article{KnochenhauerReicheBarberkaetal.1995,
  author    = {Knochenhauer, Gerald and Reiche, J{\"u}rgen and Barberka, Thomas Andreas and Woolley, Martin and Tredgold, Richard H. and Hodge, P. and Brehmer, Ludwig},
  title     = {Do perfluorianted chains always have to be twisted?},
  year      = {1995},
  abstract  = {Short perfluorinated cabon chains do not take on helical structure when they are closely packed},
  language  = {en}
}
@article{DietzelFreydankReicheetal.1995,
  author    = {Dietzel, Birgit and Freydank, A. and Reiche, J{\"u}rgen and Brehmer, Ludwig and Knoblauch, H. and Knochenhauer, Gerald and Zetzsche, Thomas},
  title     = {Mono- und Multischichten von neuen aromatischen 1,3,4-Oxadiazolen},
  year      = {1995},
  language  = {de}
}
@article{ReicheBarberkaKnochenhaueretal.1994,
  author    = {Reiche, J{\"u}rgen and Barberka, Thomas Andreas and Knochenhauer, Gerald and Woolley, Martin and Pietsch, Ullrich},
  title     = {Comprehensive structure investigation and computer modelling of perfluorododecanoic acid multilayers formed by in-vacuo thermal evaporation},
  year      = {1994},
  language  = {en}
}
@article{SchulzStillerZetzscheetal.1994,
  author    = {Schulz, Burkhard and Stiller, Burkhard and Zetzsche, Thomas and Knochenhauer, Gerald and Dietel, Reinhard and Brehmer, Ludwig},
  title     = {Crystal structure of 2,5-Di(4- methoxycarbonyl-phenyl)-1,3,4-oxadiazole characterized by AFM and IR- spectroscopy},
  year      = {1994},
  language  = {en}
}
@article{SchulzKnochenhauerBrehmeretal.1994,
  author    = {Schulz, Burkhard and Knochenhauer, Gerald and Brehmer, Ludwig and Janietz, Silvia},
  title     = {Stuctures and properties of aromatic poly(1,3,4-oxadiazole)s},
  year      = {1994},
  language  = {en}
}
@article{Knochenhauer1994,
  author    = {Knochenhauer, Gerald},
  title     = {Thin organic layers : Langmuir-Blodgett films low dimensional quantum mechanics},
  year      = {1994},
  language  = {en}
}
@article{ReicheKnochenhauerDieteletal.1997,
  author    = {Reiche, J{\"u}rgen and Knochenhauer, Gerald and Dietel, Reinhard and Freydank, Anke-Christine and Zetzsche, Thomas and Pietsch, Ullrich and Brehmer, Ludwig and Barberka, Thomas Andreas and Geue, Thomas},
  title     = {Structure of thermally treated oxadiazoleamide Langmuir-Blodgett films},
  year      = {1997},
  abstract  = {The thermal treatment of Y-type Langmuir-Blodgett (LB) films formed from the amphiphilic derivative of 2,5- diphenyl-1,3,4-oxadiazole 1 results in changes of the molecular packing. These changes have been analysed by a combination of X-ray specular reflectivity data, X-ray grazing incidence diffraction data and scanning force microscopy images, On the basis of these experimental data we have simulated possible supramolecular structures, These simulations provide insight into the intermolecular interactions giving rise to the observed structural transitions. The crystalline structure induced by thermal treatment of the LB films is characterized by a uniaxial texture, which is correlated with the dipping direction during deposition of the LB film.},
  language  = {en}
}
@article{ReicheSchulzKnochenhaueretal.1997,
  author    = {Reiche, J{\"u}rgen and Schulz, Burkhard and Knochenhauer, Gerald and Dietzel, Birgit and Freydank, Anke-Christine and Zetzsche, Thomas and Brehmer, Ludwig},
  title     = {Supramolecular structures formed from heterocyclic aromatic molecules},
  year      = {1997},
  abstract  = {This paper describes the formation and structure investigation of Langmuir monolayers and Langmuir-Blodgett multilayers formed from amphiphilic derivatives of 2,5-diphenyl-1,3,4-oxadiazole. The 2,5-diphenyl-1,3,4-oxadiazole group as a functional unit with interesting physical and chemical properties is maintained, while the head group, the length of the alkyl chain and the structure of the coupling unit between aromatic and aliphatic part of these linear short-chain amphiphiles is systematically varied in order to explore the influence of this change on the film forming properties and the stability of Langmuir and Langmuir-Blodgett films. Molecular mechanics simulations are shown by these systematic variations to be suitable for the prediction of optimal chemical structures allowing for a stable stratified molecular packing. The combination of a detailed structure investigation of the multilayers based on scanning force microscopy and X-ray data with molecular mechanics simulations yields an insight into the packing of the molecules and the intermolecular interactions.},
  language  = {en}
}
@article{SchulzBrehmerKnochenhauer1995,
  author    = {Schulz, Burkhard and Brehmer, Ludwig and Knochenhauer, Gerald},
  title     = {Supramolecular structures of aromatic 1,3,4-oxadiazole solids},
  year      = {1995},
  language  = {en}
}
@article{WuestneckPrescherKatholyetal.2000,
  author    = {W{\"u}stneck, Rainer and Prescher, Dietrich and Katholy, Stefan and Knochenhauer, Gerald and Brehmer, Ludwig},
  title     = {Surface dilatational rheological study of the trans-cis isomerisation of copolymers with trifluoromethoxy substituted metacrylate monolayers},
  issn      = {0927-7757},
  year      = {2000},
  language  = {en}
}
@article{ReicheFreydankHelmsetal.1999,
  author    = {Reiche, J{\"u}rgen and Freydank, Anke-Christine and Helms, Andreas and Geue, Thomas and Schulz, Burkhard and Brehmer, Ludwig and Stiller, Burkhard and Knochenhauer, Gerald},
  title     = {Vacuum deposition films of oxadiazole compounds : formation and structure investigation},
  year      = {1999},
  abstract  = {The search for alternative routes of organic thin film formation is stimulated by the outstanding properties of these films in such fields as nonlinear optics, photonic data processing and molecular electronics. The formation of highly ordered multilayer structures by thermal vacuum deposition (VD) of organic compounds is an essential step toward the application of supramolecular organic architectures in technical systems. The VD of an amphiphilic substituted 2,5- diphenylene-1,3,4-oxadiazole 1 onto silicon substrates at defined temperature was used for the formation of ultrathin films. The structural data obtained for the VD-films of oxadiazole 1 by means of X-ray reflectivity, X-ray grazing incidence diffraction and atomic force microscopy (AFM) investigations indicate the formation of well ordered oxadiazole multilayers. The structure of the VD-multilayers is compared with that of Langmuir-Blodgett (LB) films and thermally treated LB-multilayers prepared from the same compound.},
  language  = {en}
}
@article{OrgzallLorenzMikatetal.1999,
  author    = {Orgzall, Ingo and Lorenz, Bernd and Mikat, J{\"u}rgen E. R. and Reck, G{\"u}nter and Knochenhauer, Gerald and Schulz, Burkhard},
  title     = {Phase transition in 1,3,4-oxadiazole crystals under high pressure},
  year      = {1999},
  abstract  = {Crystalline 2,5-di(4-nitrophenyl)-1,3,4-oxadiazole (DNO) has been investigated at pressures up to 5 GPa using Raman and optical spectroscopy as well as energy dispersive X-ray techniques. At ambient pressure DNO shows an orthorhombic unit cell (a = 0.5448 nm, b = 1.2758 nm, c = 1.9720 nm, density 1.513 g cm-3) with an appropriate space group Pbcn. From Raman spectroscopic investigations three phase transitions have been detected at 0.88, 1.28, and 2.2 GPa, respectively. These transitions have also been confirmed by absorption spectroscopy and X-ray measurements. Molecular modeling simulations have considerably contributed to the interpretation of the X-ray diffractograms. In general, the nearly flat structure of the oxadiazole molecule is preserved during the transitions. All subsequent structures are characterized by a stack-like arrangement of the DNO molecules. Only the mutual position of these molecular stacks changes due to the transformations so that this process may be described as a topotactical reaction. Phases II and III show a monoclinic symmetry with space group P21/c with cell parameters a = 1.990 nm, b = 0.500 nm, c = 1.240 nm, ß = 91.7°, density 1.681 g cm-3 (phase II, determined at 1. 1 GPa) and a = 1.890 nm, b = 0.510 nm, C = 1.242 nm, ß = 89.0°, density 1.733 g cm-3 (phase 111, determined at 2.0 GPa), respectively. The high-pressure phase IV stable at least up to 5 GPa shows again an orthorhombic structure with space group Pccn with corresponding cell parameters at 2.9 GPa: a = 0.465 nm, b = 1.920 nm, c = 1.230 nm and density 1.857 g cm-3 . For the first phase a blue pressure shift of the onset of absorption by about 0.032 eV GPa has been observed that may be explained by pressure influences on the electronic conjugation of the molecule. In the intermediate and high-pressure phases II-IV the onset of absorption shifts to increased wavelengths due to larger intermolecular interactions and enhanced excitation delocalization with decreasing intermolecular spacing.},
  language  = {en}
}
@article{KnochenhauerPenacoradaReicheetal.1999,
  author    = {Knochenhauer, Gerald and Penacorada, Florencio and Reiche, J{\"u}rgen and Brehmer, Ludwig and Tredgold, Richard H. and Barberka, Thomas Andreas},
  title     = {Multilayers of perfluorinated fatty acids},
  year      = {1999},
  abstract  = {We have formed Y layers of perfluorododecanoic acid CF3(CF2)10COOH by thermal evaporation in vacuo and of perfluorotetradecanoic acid CF3(CF2)12COOH by thermal evaporation and by the Langmuir-Blodgett (LB) technique. We have obtained the bilayer spacing of both these materials by X-ray diffraction and have also studied the in-plane structure of these materials by means of grazing incidence diffraction (GID). Computer modelling was used to interpret the results obtained. For the perfluorododecanoic acid, we find two stable untwisted phases at 25°C and a combination of these two predicts both the Bragg peaks arising from the layer structure and the GID results. Our experimental results show that the perfluorotetradecanoic acid exists in the generally accepted helical structure. Computer modelling leads to the conclusion that closely packed perfluorinated chains with 12 or less carbon atoms should exist in an untwisted state while molecules having more than 12 carbon atoms show the onset of the helical conformation.},
  language  = {en}
}