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1,051 results on '"lattice vibrations"'

103. To the organic world: carbon.

Author

Cotterill, Rodney

Abstract

'tis, we musicians know, the C Major of this life. Paintings and museum reconstructions depicting the activities of medieval alchemists can easily give the wrong impression of the chemical knowledge of that period. Inanimate objects such as crystals are seen sharing shelves with the preserved bodies of small creatures, a common feature of the early laboratory. This could be taken to suggest that the scientists of those days had grasped the unity of chemistry: that in spite of great differences in their external appearance, Nature makes no distinction between chemical combinations in living and dead substances. Nothing could be farther from the truth. The universally held belief was that the matter contained in living organisms possessed an essential extra ingredient, a vital force, the mysterious origin of which was attributable to divine powers. This attitude was epitomized in the succinct classification to be found in the book Cours de Chyme, published by Nicholas Lemery in 1685. His division is still to be found in the standard first question of a popular parlour game: ‘animal, vegetable or mineral?’. By the end of the eighteenth century, the vital force theory was in rapid decline. Antoine Lavoisier, analyzing typical organic compounds, found them to contain inorganic substances such as hydrogen, oxygen, nitrogen, carbon, sulphur and phosphorus. The basic principles that govern chemical change, such as conservation of total mass, were being established during this period, and in 1844 Jöns Berzelius showed that they apply to all matter irrespective of whether it is inorganic or organic. [ABSTRACT FROM AUTHOR]

Published
2008
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137. Fast mapping of inhomogeneities in the popular metallic perovskite Nb:SrTiO3 by confocal Raman microscopy.

Author

RodENbücher, Christian, Jauß, Andrea, Havel, Viktor, Waser, Rainer, and Szot, Kristof

Subjects
*RAMAN microscopy, *PEROVSKITE, *OXIDE minerals, *MICROMETRY, *MICROSCOPY
Abstract

Confocal Raman microscopy was applied in order to investigate the homogeneity of donor doping in Nb:SrTiO3 single crystals. Measurements of local Raman spectra revealed a systematic relation between the intensity of the Raman signal and the donor content of the crystals. We successfully elaborated a correspondence between the electronic structure and the intensity of the Raman lines using a crystal with macroscopic inhomogeneity as a demonstration sample. By mapping the distribution of the intensity of the Raman signal, we identified a characteristic inhomogeneous structure related to the presence of clusters with sizes of 5 µm to 20 µm, indicating inhomogeneous donor distribution caused by flaws introduced during crystal growth. Hence, we propose confocal Raman microscopy as a convenient technique for investigating the homogeneity and quality of doped perovskite surfaces, which are needed for various technological applications. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Published
2014
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138. Phase equilibrium of a CuInSe2–CuInS2 pseudobinary system studied by combined first-principles calculations and cluster expansion Monte Carlo simulations.

Author

Tao Xue, Hong, Tang, Fu Ling, Kang Li, Xiao, Cheng Wan, Fu, Jiang Lu, Wen, Yuan Rui, Zhi, and Dong Feng, Yu

Subjects
*COPPER compounds, *INDIUM selenide, *PHASE equilibrium, *BINARY metallic systems, *METAL clusters, *MONTE Carlo method
Abstract

Abstract: We report the phase diagram of a CuInSe2–CuInS2 pseudobinary system calculated by a combination of first-principles calculations based on density functional theory, cluster expansion, and Monte Carlo simulations. All formation energies of CuIn(Se1−x S x )2 (CISS) alloys are positive, indicating that CISS alloy is a miscibility gap system and has a tendency to phase separation. The phase diagram computed with conventional cluster expansion shows a miscibility gap with consolute temperature T C =170K. The contribution of lattice vibrations lowers T C to 130K. The miscibility gaps for the CuInSe2–CuInS2 system are predicted to be asymmetric. The effect of lattice vibrations on the miscibility gap is found to be large, and the size mismatch mechanism can be used to explain the large vibrational effect in the CuInSe2–CuInS2 system. [Copyright &y& Elsevier]

Published
2014
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139. RETRACTED ARTICLE: Quantum effects on translation and rotation of molecular chlorine in solid para-hydrogen.

Author

Accardi, Antonio and Schmidt, Burkhard

Subjects
*QUANTUM chemistry, *CHLORINE, *PARAHYDROGEN, *MOLECULAR rotation, *FACE centered cubic structure
Abstract

Structure and quantum effects of a Cl2molecule embedded in fcc and hcp para-hydrogen (pH2) crystals are investigated in the zero-temperature limit. The interaction is modelled in terms of Cl2–pH2and pH2–pH2pair potentials fromab initioCCSD(T) and MP2 calculations. Translational and rotational motions of the molecules are described within three-dimensional anharmonic Einstein and Devonshire models, respectively, where the crystals are either treated as rigid or allowed to relax. The pH2molecules, as well as the heavier Cl2molecule, show large translational zero-point energies (ZPEs) and undergo large-amplitude translational motions. This gives rise to substantial reductions in the cohesive energies and expansions of the lattices, in agreement with experimental results for pure hydrogen crystals. The rotational dynamics of the Cl2impurity is restricted to small-amplitude librations, again with high librational ZPEs, which are described in terms of two-dimensional non-degenerate anharmonic oscillators. The lattice relaxation causes qualitative changes of the rotational energy surfaces, which finally favour librations around the crystallographic directions pointing towards the nearest neighbours, both for fcc and hcp lattices. Implications on the reactant orientation in the experimentally observed laser-induced chemical reaction, Cl + H2→ HCl + H, are discussed. [ABSTRACT FROM AUTHOR]

Published
2014
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140. Lattice dynamics of palladium in the presence of electronic correlations

Author

W. H. Appelt, Andreas Östlin, Dieter Vollhardt, Liviu Chioncel, Michael Sekania, I. Leonov, and I. Di Marco

Subjects
Lattice dynamics, media_common.quotation_subject, LATTICE VIBRATIONS, Library science, FOS: Physical sciences, Lattice vibration, 02 engineering and technology, GROUND STATE PROPERTIES, CORRELATION EFFECT, DYNAMICAL MEAN-FIELD THEORY, 01 natural sciences, Condensed Matter - Strongly Correlated Electrons, Lottery, Condensed Matter::Materials Science, Promotion (rank), Dynamical mean field theory, State (polity), MEAN FIELD THEORY, Hospitality, Political science, 0103 physical sciences, ddc:530, DENSITY FUNCTIONAL THEORY, PHONON DISPERSIONS, PHONON FREQUENCIES, 010306 general physics, media_common, Government, IONIC DISPLACEMENT, Strongly Correlated Electrons (cond-mat.str-el), business.industry, PALLADIUM, ELECTRONIC CORRELATION, PHONONS, 021001 nanoscience & nanotechnology, GROUND STATE, TEMPERATURE RANGE, 0210 nano-technology, business
Abstract

We compute the phonon dispersion, density of states, and the Gr\"uneisen parameters of bulk palladium in the combined density functional theory (DFT) and dynamical mean-field theory (DMFT). We find good agreement with experimental results for ground state properties (equilibrium lattice parameter and bulk modulus) and the experimentally measured phonon spectra. We demonstrate that at temperatures $T \lesssim 20~K$ the phonon frequency in the vicinity of the Kohn anomaly, $\omega_{T1}({\bf q}_{K})$, strongly decreases. This is in contrast to DFT where this frequency remains essentially constant in the whole temperature range. Apparently correlation effects reduce the restoring force of the ionic displacements at low temperatures, leading to a mode softening., Comment: minor revisions

Published
2020

141. Lattice dynamics and spontaneous magnetodielectric effect in ilmenite CoTiO$_3$

Author

Peter C. M. Christianen, A. M. Balbashov, N. N. Novikova, N. V. Siverin, Roman V. Pisarev, R. M. Dubrovin, V. A. Chernyshev, and M. A. Prosnikov

Subjects
Phonon, Physics::Optics, 02 engineering and technology, 01 natural sciences, Materials Chemistry, Condensed Matter - Materials Science, Condensed matter physics, Metals and Alloys, COBALT COMPOUNDS, SINGLE CRYSTALS, PHONONS, 021001 nanoscience & nanotechnology, DFT CALCULATIONS, MAGNETIC EXCITATIONS, Magnetic field, Mechanics of Materials, RAMAN SPECTROSCOPY, symbols, INFRARED SPECTROSCOPY, 0210 nano-technology, LATTICE DYNAMICS, COTIO3, Materials science, ZERO MAGNETIC FIELDS, LATTICE VIBRATIONS, DIELECTRIC SPECTROSCOPY, Infrared spectroscopy, FOS: Physical sciences, PERMITTIVITY, Dielectric, ANTIFERROMAGNETIC ORDERING TEMPERATURE, TITANIUM COMPOUNDS, RAMAN-ACTIVE PHONON, 010402 general chemistry, SPECTROSCOPIC TECHNIQUE, symbols.namesake, ANTIFERROMAGNETISM, Soft Condensed Matter and Nanomaterials, TECHNOLOGICAL APPLICATIONS, Antiferromagnetism, MAGNETO-DIELECTRIC EFFECTS, Spins, Mechanical Engineering, ILMENITE, Materials Science (cond-mat.mtrl-sci), 0104 chemical sciences, DIELECTRIC PERMITTIVITIES, ELECTROMAGNETS, Raman spectroscopy, Single crystal
Abstract

Ilmenite-type crystals find a variety of technological applications due to their intriguing physical properties. We present the results of the lattice dynamics studies of honeycomb antiferromagnetic ilmenite CoTiO$_3$ single crystal by the complementary polarized infrared, Raman, and dielectric spectroscopic techniques that are supplemented by the DFT calculations. The frequencies and symmetries of all predicted infrared and Raman active phonons were uniquely identified. Furthermore, it was found that the dielectric permittivity demonstrates distinct changes below antiferromagnetic ordering temperature in zero magnetic field due to spontaneous magnetodielectric effect. Our results establish the reliable basis for further investigation of the coupling of phonons with spins, magnetic excitations and other physical phenomena of this promising material., Comment: 11 pages, 8 figures, 2 tables, 2 tables

Published
2020
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142. Effect of dopant nature on structures and lattice dynamics of proton-conducting BaZrO3.

Author

Zeudmi Sahraoui, D. and Mineva, T.

Subjects
*DOPING agents (Chemistry), *PROTON conductivity, *ZIRCONIUM oxide, *CHEMICAL structure, *SYMMETRY (Physics), *CHEMICAL bonds, *VIBRATION (Mechanics)
Abstract

Abstract: The influence of the acceptor-dopants on the local and long range structures and lattice vibrations of barium zirconate has been studied with Density Functional Theory (DFT) based periodic approach. Structural details of BaZr1−xMxHxO3 (M=In and Sc, and x=0.125, 0.25 and 0.375) with protonic defects in three different oxygen configurations are presented and discussed in relation with the results for Y-doped barium zirconates, obtained previously with the same methodology. The oxide symmetry and the short and long range structural arrangements in the M-rich and Zr-rich regions were established nearly independent on the dopant chemical nature, concentration and arrangement in the cell. The O H bond formation is however strongly influenced by the dopant nature, which is associated with the differences in dopant–oxygen bond character. The computed lattice vibrations in zirconates with Y, In and Sc dopants showed that the O H vibrations vary by 250–1500cm−1 depending on the acceptor-dopant. [Copyright &y& Elsevier]

Published
2013
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143. Lattice defects induce microtubule self-renewal

Author

Ariane Abrieu, Laura Schaedel, Laurent Blanchoin, Charlotte Aumeier, Manuel Théry, Denis Chrétien, Sarah Triclin, Karin John, Jérémie Gaillard, CytoMorphoLab, Physiologie cellulaire et végétale (LPCV), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Génétique et Développement de Rennes (IGDR), Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique )-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre de recherche en Biologie Cellulaire (CRBM), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), French National Research Agency (ANR) ANR-16-CE11-0017-01 ANR-12-BSV5-0004-01 ANR-14-CE09-0014-02 ANR-18-CE13-0001, Human Frontier Science Program RGY0088, European Research Council (ERC) 771599 741773, Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Centre de recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE13-0001,APERTuRe,Une nouvelle perspective sur la régulation des microtubules(2018), Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Physiologie cellulaire et végétale (LPCV), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut National de la Recherche Agronomique (INRA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lattice dynamics, Dimer, [SDV]Life Sciences [q-bio], General Physics and Astronomy, Crystal structure, Self renewal, Instability, 01 natural sciences, Microtubules, Article, Lattice vibrations, 010305 fluids & plasmas, Quantitative Biology::Subcellular Processes, 03 medical and health sciences, chemistry.chemical_compound, Microtubule, Lattice (order), 0103 physical sciences, 010306 general physics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, Physics, Thermal forces, 0303 health sciences, Structural defect, biology, Chemistry, 030302 biochemistry & molecular biology, Model mechanisms, Dissipative dynamics, Dynamics, Tubulin, Lattice defects, biology.protein, Biophysics, Lattice structures, Passive materials, Defects
Abstract

The dynamic instability of microtubules is powered by the addition and removal of tubulin dimers at the ends of the microtubule. Apart from the end, the microtubule shaft is not considered to be dynamic. However recent evidence suggests that free dimers can be incorporated into the shaft of a microtubule damaged by mechanical stress. Here we explored whether dimer exchange was a core property of the microtubule lattice independently of any external constraint. We found that dimers can be removed from and incorporated into the lattice at sites along the microtubule shaft. Furthermore, we showed by experiment and by modeling that rapid dimer renewal requires structural defects in the lattice, which occur in fast growing microtubules. Hence long-lived microtubules have the capacity to self-renew despite their apparent stability and thereby can potentially regulate signaling pathways and structural rearrangements associated with tubulin-dimer exchange at sites along their entire length.

Published
2019

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