TY - GEN A1 - Bachhuber, Frederik A1 - Appen, Jörg von A1 - Dronskowski, Richard A1 - Schmidt, Peer A1 - Nilges, Tom A1 - Pfitzner, Arno A1 - Weihrich, Richard T1 - Van der Waals interactions in selected allotropes of phosphorus T2 - Zeitschrift für Kristallografie N2 - Selected allotropes of phosphorus are investigated by different levels of density functional theory (DFT) calculations to evaluate the relative stability orders with a special focus on the role of van der Waals interactions.Phosphorus is an excellent reference system with a large number of allotropes. Starting from low-dimensional molecular (0D, white P) and polymer structures (1D, P nanorods) to layered (2D, black P) and tubular structures (2D and 3D, crystalline forms of red P), covalent structure motifs are interconnected by van der Waals interactions. They are a key factor for the correct energetic description of all P allotropes. A comparative study is carried out within the local density approximation (LDA) and the generalized gradient approximation (GGA), with and without implementation of a dispersion correction by Grimme (GGA-D2). Our intention is to achieve a reasonable agreement of our calculations with experimental data, the plausibility of energy values, and the treatment of long-range interactions. The effect of van der Waals interactions is exemplified for the interlayer distances of black phosphorous and its electronic structure. KW - allotropes KW - band structure KW - DFT KW - phosphorous KW - stability KW - van der Waals Y1 - 2015 U6 - https://doi.org/10.1515/zkri-2014-1800 SN - 2196-7105 VL - 230 IS - 2 SP - 107 EP - 115 ER - TY - GEN A1 - Bachhuber, Frederik A1 - Appen, Jörg von A1 - Dronskowski, Richard A1 - Schmidt, Peer A1 - Nilges, Tom A1 - Pfitzner, Arno A1 - Weihrich, Richard T1 - The Extended Stability Range of Phosphorus Allotropes T2 - Angewandte Chemie / International edition N2 - Phosphorus displays fascinating structural diversity and the discovery of new modifications continues to attract attention. In this work, a complete stability range of known and novel crystalline allotropes of phosphorus is described for the first time. This includes recently discovered tubular modifications and the prediction of not-yet-known crystal structures of [P12] nanorods and not-yet-isolated [P14] nanorods. Despite significant structural differences, all P allotropes consist of covalent substructures, which are held together by van der Waals interactions. Their correct reproduction by ab initio calculations is a core issue of current research. While some predictions with the established DFT functionals GGA and LDA differ significantly from experimental data in the description of the P allotropes, consistently excellent agreement with the GGA-D2 approach is used to predict the solid structures of the P nanorods. KW - density functional calculations KW - phosphorus KW - structure elucidation KW - van der Waals interactions Y1 - 2014 UR - http://onlinelibrary.wiley.com/doi/10.1002/anie.201404147/full U6 - https://doi.org/10.1002/anie.201404147 SN - 1521-3773 VL - 53 IS - 43 SP - 11629 EP - 11633 ER - TY - GEN A1 - Wolpert, Benjamin A1 - Leitl, Michael A1 - Pfitzner, Arno A1 - Mirsky, Vladimir M. T1 - Chemosensitive properties of electrically conductive Cu(I)-compounds at room temperature T2 - Sensors and Actuators B: Chemical N2 - Changes of the electrical conductance of a number of inorganic copper(I) conductive compounds including Cu₁₂Sb₄S₁₃,CU₂O, CuI, CuBr and CuCl were tested on exposure to different gases and vapors, including ammonia, nitrogen monoxide, octanethiol, hydrogen chloride, acetic acid, formic acid, ethanol, humidity and piperidine. The sensitivity of the resistivity to ammonia was estimated as 2.7%/ppm for CuBr,1.4%/ppm for Cu₂O, 1.2%/ppm for CuCl, 0.013%/ppm for CuI, but only 0.0028%/ppm for Cu₁₂Sb₄S₁₃. The highest selectivity for ammonia was observed for Cu₁₂Sb₄S₁₃. The sensitivity patterns of these materials to the tested gases and vapors are very different which makes them applicable for sensor arrays for identification and quantification of these species. KW - Chemical sensor KW - Gas sensor KW - Ammonia sensor KW - Conductometric sensor KW - Chemoresistor KW - Copper(I) Y1 - 2008 U6 - https://doi.org/10.1016/j.snb.2008.06.047 SN - 0925-4005 VL - 134 IS - 2 SP - 839 EP - 842 ER -