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https://read.qxmd.com/read/30896166/a-three-dimensional-reference-interaction-site-model-self-consistent-field-study-on-the-coordination-structure-and-excitation-spectra-of-cu-ii-water-complexes-in-aqueous-solution
#1
Chen Yang, Yoshihiro Watanabe, Norio Yoshida, Haruyuki Nakano
The molecular and solvation structures of the hydrated Cu2+ ion and their excitation spectra were investigated using the Kohn-Sham density functional theory (DFT) and the three-dimensional reference interaction site model (3D-RISM) self-consistent field method. Five stable geometrical structures were found to exist in aqueous solution: the distorted octahedral [Cu(H2O)6]2+ in Ci and D2h symmetry, the square pyramidal and trigonal bipyramidal [Cu(H2O)5]2+, and the square planar [Cu(H2O)4]2+. The distorted octahedral in Ci symetry are prefereed in the [Cu(H2O)6]2+, and the squre pyramidal and trigonal bipyramidal [Cu(H2O)5]2+ show almost same stability...
March 21, 2019: Journal of Physical Chemistry. A
https://read.qxmd.com/read/30847459/the-role-of-ligand-to-metal-charge-transfer-states-on-the-luminescence-of-europium-complexes-with-18-membered-macrocyclic-ligands
#2
Aline Nonat, David Esteban-Gómez, Laura Valencia, Paulo Pérez-Lourido, José Luis Barriada, Loïc J Charbonnière, Carlos Platas-Iglesias
We report a detailed study of the photophysical properties of EuIII and TbIII complexes with two ligands based on a 3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane platform containing either four pyridine-2yl-methyl (L1) or four hydroxyethyl (L2) pendant arms. The [TbL1]3+ and [TbL2]3+ complexes present moderate luminescence quantum yields upon excitation through the ligand bands (φH2O = 7.4 and 21%, respectively). The [EuL2]3+ complex displays a relatively low quantum yield in H2O (φH2O = 1.6%) that increases considerably in D2O (φD2O = 5...
March 8, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
https://read.qxmd.com/read/30822002/rigorous-results-for-the-ground-states-of-the-spin-2-bose-hubbard-model
#3
Hong Yang, Hosho Katsura
We present rigorous and universal results for the ground states of the f=2 spinor Bose-Hubbard model. The model includes three two-body on-site interaction terms, two of which are spin dependent while the other one is spin independent. We prove that, depending only on the coefficients of the two spin-dependent terms, the ground state exhibits maximum or minimum total spin or SU(5) ferromagnetism. Exact ground-state degeneracies and the forms of ground-state wave function are also determined in each case. All these results are valid regardless of dimension, lattice structure, or particle number...
February 8, 2019: Physical Review Letters
https://read.qxmd.com/read/30785746/symmetry-broken-many-body-excited-states-of-the-gaseous-atomic-double-well-bose-einstein-condensate
#4
David J Masiello, William Parker Reinhardt
Macroscopic, many-body self-trapped and quantum superposition states of the gaseous double-well Bose-Einstein condensate (BEC) are investigated within the context of a multiconfigurational bosonic self-consistent field theory based upon underlying spatially symmetry-broken one-body wave functions. To aid in the interpretation of our results, an approximate model is constructed in the extreme Fock state limit, in which self-trapped and superposition states emerge in the many-body spectrum, striking a delicate balance between the degree of symmetry breaking, the effects of the condensate's mean field, and that of atomic correlation...
February 20, 2019: Journal of Physical Chemistry. A
https://read.qxmd.com/read/30745337/excitable-dynamics-of-ras-triggers-spontaneous-symmetry-breaking-of-pip3-signaling-in-motile-cells
#5
Seiya Fukushima, Satomi Matsuoka, Masahiro Ueda
Spontaneous cell movement is underpinned by an asymmetric distribution of signaling molecules including small G proteins and phosphoinositides on the cell membrane. A fundamental question lies in the molecular network for the spontaneous symmetry breaking. Here we report that spatiotemporal dynamics of GTP bound Ras (Ras-GTP) breaks the symmetry due to excitability even in the absence of extracellular spatial cues and downstream signaling activities. A stochastic excitation of local and transient Ras activation induced PIP3 accumulation via direct interaction with PI3K, causing tightly coupled traveling waves propagating along the membrane...
February 11, 2019: Journal of Cell Science
https://read.qxmd.com/read/30675786/symmetry-dependent-vibrational-circular-dichroism-enhancement-in-co-ii-salicylaldiminato-complexes
#6
Gennaro Pescitelli, Steffen Lüdeke, Marcin Górecki, Lorenzo Di Bari
Chiral coordination compounds of Co(II) and other metal ions with low-lying excited states (LLES) display enhanced vibrational circular dichroism (VCD) spectra which can be used for sensing purposes. In addition to the enhancement, a series of Co(II) salicylaldiminato complexes exhibit unique VCD spectra which are almost monosignate, instead of showing the usual alternation of positive and negative bands. The two phenomena of VCD enhancement and monosignate appearance are strictly related and symmetry-dependent...
January 24, 2019: Journal of Physical Chemistry Letters
https://read.qxmd.com/read/30668122/anisotropic-flow-control-and-gate-modulation-of-hybrid-phonon-polaritons
#7
Francisco Carlos Barbosa Maia, Brian O'Callahan, Alisson Ronieri Cadore, Ingrid David Barcelos, Leonardo Cristiano Campos, Kenji Watanabe, Takashi Taniguchi, Christoph Deneke, A Belyanin, Markus B Raschke, Raul O Freitas
Light-matter interaction in two-dimensional photonic materials allows for confinement and manipulation of free-space radiation in sub-wavelength scales. Most notably, the van der Waals heterostructure comprising graphene (G) and hexagonal Boron Nitride (hBN) provides for gate-tunable hybrid hyperbolic plasmon phonon-polaritons (HP3 ). Here, we present anisotropic flow control and gate voltage modulation of HP3 modes in G-hBN lying on air-Au microstructured substrate. Using broadband infrared synchrotron radiation coupled to a scattering-type near-field optical microscope, we launch HP3 waves in both hBN Reststrahlen bands and observe directional propagation across in-plane heterointerfaces created at the air-Au junction...
January 22, 2019: Nano Letters
https://read.qxmd.com/read/30647894/effects-of-coordination-sphere-on-unusually-large-zero-field-splitting-and-slow-magnetic-relaxation-in-trigonally-symmetric-molecules
#8
Kelsey A Schulte, Kuduva R Vignesh, Kim R Dunbar
Geometric control in mononuclear complexes has come to the forefront in the field of molecular magnets due to its profound effects on relaxation pathways and blocking temperature in single molecule magnets (SMMs). Herein we report the synthesis and magnetic characterization of six trigonally symmetric, divalent Fe, Co, and Ni molecules, with the rigid geometry enforced via the use of the tris-anionic, tetradentate ligand MST ( N , N ', N ''-[2,2',2''-nitrilotris-(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamide))...
December 28, 2018: Chemical Science
https://read.qxmd.com/read/30628607/on-the-border-between-localization-and-delocalization-tris-iminoxolene-titanium-iv
#9
Travis Marshall-Roth, Kun Yao, John A Parkhill, Seth N Brown
The tris(aminophenol) ligand tris(4-methyl-2-(3',5'-di-tert-butyl-2'-hydroxyphenylamino)phenyl)amine, MeClampH6, reacts with Ti(OiPr)4 to give, after exposure to air, the dark purple, neutral, diamagnetic complex (MeClamp)Ti. The compound is six-coordinate, with an uncoordinated central nitrogen (Ti-N = 2.8274(12) Å), and contains titanium(iv) and a doubly oxidized ligand, formally a bis(iminosemiquinone)-mono(amidophenoxide). The compound is unsymmetrical in the solid state, though the three ligands are equivalent on the NMR timescale in solution...
January 10, 2019: Dalton Transactions: An International Journal of Inorganic Chemistry
https://read.qxmd.com/read/30608790/quantum-groups-as-hidden-symmetries-of-quantum-impurities
#10
E Yakaboylu, M Shkolnikov, M Lemeshko
We present an approach to interacting quantum many-body systems based on the notion of quantum groups, also known as q-deformed Lie algebras. In particular, we show that, if the symmetry of a free quantum particle corresponds to a Lie group G, in the presence of a many-body environment this particle can be described by a deformed group, G_{q}. Crucially, the single deformation parameter, q, contains all the information about the many-particle interactions in the system. We exemplify our approach by considering a quantum rotor interacting with a bath of bosons, and demonstrate that extracting the value of q from closed-form solutions in the perturbative regime allows one to predict the behavior of the system for arbitrary values of the impurity-bath coupling strength, in good agreement with nonperturbative calculations...
December 21, 2018: Physical Review Letters
https://read.qxmd.com/read/30603898/the-symmetry-breaking-phenomenon-in-heteronine-analogues-due-to-the-pseudo-jahn-teller-effect
#11
Ali Reza Ilkhani
The pseudo Jahn-Teller effect (PJTE) is employed in C8 AH8 (A = O, S, Se, Te), and C8 EH8 + 1 (E = N, P, As, Sb) with planar configurations to show symmetry breaking phenomena (SBP) in heteronine analogues, and to explain why molecules with (C2v ) high-symmetry configurations cannot maintain planarity and pucker to their (C2 ) and (Cs ) lower-symmetry structures, respectively. To investigate this phenomenon, geometry optimization and frequency calculations through the density functional B3LYP method using the cc-pVTZ basis set (for Te, and Sb cc-pVTZ-PP) were carried out for all compounds in the series...
January 2, 2019: Journal of Molecular Modeling
https://read.qxmd.com/read/30597437/novel-triazole-thiole-ligand-and-some-of-its-metal-chelates-synthesis-structure-charactertization-thermal-behavior-in-comparison-withcomputational-caculations-andbiological-activities
#12
Ehab M Zayed, M A Zayed, Hayam A Abd El Salam, Mahmoud A Noamaan
Structural and molecular properties of HL, 4-amino-5-(2,2-dichloro-1-methylcyclopropyl)-4H-1,2,4-triazole-3-thiol toward the transition metal ions namely Fe(III), Co(II) and Ni(II) had been studied using elemental analyses, magnetic, electronic, FT- IR, 1 H-NMR and Thermal analyses (TGA and DTA). The interpretation of thermal decomposition stages had been evaluated. The computations had been done by software of Gaussian 09W package. The geometries of triazole-thiole ligand and its metal chelates were fully optimized using density functional theory B3LYP method...
December 22, 2018: Computational Biology and Chemistry
https://read.qxmd.com/read/30577631/full-dimensional-ab-initio-potential-energy-surface-and-vibrational-energy-levels-of-li%C3%A2-h
#13
Michiko Ahn Furudate, Denis Hagebaum-Reignier, Gwang-Hi Jeung
We built a full-dimensional analytical potential energy surface of the ground electronic state of Li₂H from ca. 20,000 ab initio multi-reference configuration interaction calculations, including core⁻valence correlation effects. The surface is flexible enough to accurately describe the three dissociation channels: Li (2s ²S) + LiH (¹Σ⁺), Li₂ (¹Σg ⁺) + H (1s ²S) and 2Li (2s ²S) + H (1s ²S). Using a local fit of this surface, we calculated pure ( J = 0) vibrational states of Li₂H up to the barrier to linearity (ca...
December 21, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://read.qxmd.com/read/30576765/developing-a-new-approach-for-biological-optimal-control-problems-application-to-optimization-of-laccase-production-with-a-comparison-between-response-surface-methodology-and-novel-geometric-procedure
#14
Zahra Ghobadi Nejad, Seyed Mehdi Borghei, Soheila Yaghmaei, Atefeh Hasan-Zadeh
Laccase production by indigenous fungus, Phanerochaete chrysosporium, requires solving optimal problems to determine the maximum production of the enzyme within a definite time period and conditions specified in the solid-state fermentation process. For this purpose, parallel to response surface methodology, an analytical approach has been proposed based on the advanced concepts of Poisson geometry and Lie groups, which lead to a system of the Hamiltonian equations. Despite the dating of the Hamiltonian approach to solving biological problems, the novelty of this paper is based on the expression of a Hamiltonian system in notions of Poisson geometry, Lie algebras and symmetry groups and first integrals...
December 18, 2018: Mathematical Biosciences
https://read.qxmd.com/read/30540470/a-combined-automated-reaction-pathway-searches-and-sparse-modeling-analysis-for-catalytic-properties-of-lowest-energy-twins-of-cu-13
#15
Takeshi Iwasa, Takaaki Sato, Makito Takagi, Min Gao, Andrey Lyalin, Masato Kobayashi, Ken-Ichi Shimizu, Satoshi Maeda, Tetsuya Taketsugu
In nanocatalysis a growing attention has recently been given to investigation of energetically low-lying structural isomers of atomic clusters, because some isomers can demonstrate better catalytic activity than the most stable structures. In this study, we present a comparative investigation of a catalytic activity for NO dissociation of a pair of the energetically degenerated isomers of Cu13 cluster having C2 and Cs symmetries. It is shown that although these isomers have similar structural, electronic, and optical properties, they can possess very different catalytic activity...
December 12, 2018: Journal of Physical Chemistry. A
https://read.qxmd.com/read/30467170/molecular-to-organismal-chirality-is-induced-by-the-conserved-myosin-1d
#16
G Lebreton, C Géminard, F Lapraz, S Pyrpassopoulos, D Cerezo, P Spéder, E M Ostap, S Noselli
The emergence of asymmetry from an initially symmetrical state is a universal transition in nature. Living organisms show asymmetries at the molecular, cellular, tissular, and organismal level. However, whether and how multilevel asymmetries are related remains unclear. In this study, we show that Drosophila myosin 1D (Myo1D) and myosin 1C (Myo1C) are sufficient to generate de novo directional twisting of cells, single organs, or the whole body in opposite directions. Directionality lies in the myosins' motor domain and is swappable between Myo1D and Myo1C...
November 23, 2018: Science
https://read.qxmd.com/read/30466266/global-elucidation-of-broken-symmetry-solutions-to-the-independent-particle-model-through-a-lie-algebraic-approach
#17
Lee M Thompson
Broken symmetry solutions-solutions to the independent particle model that do not obey all symmetries required by the Hamiltonian-have attracted significant interest for capturing multireference properties with mean-field scaling. However, identification and optimization of broken-symmetry solutions is difficult owing to the non-linear nature of the self-consistent field (SCF) equations, particularly for solutions belonging to low-symmetry subgroups and where multiple broken symmetry solutions are sought. Linearization of SCF solution space results in the Lie algebra, which this work utilizes as a framework for elucidation of the set of solutions that exist at the desired symmetry...
November 21, 2018: Journal of Chemical Physics
https://read.qxmd.com/read/30444598/electronic-and-geometric-structure-optical-properties-and-excited-state-behavior-in-atomically-precise-thiolate-stabilized-noble-metal-nanoclusters
#18
Christine M Aikens
Ligand-protected noble metal nanoclusters are of interest for their potential applications in areas such as bioimaging, catalysis, photocatalysis, and solar energy harvesting. These nanoclusters can be prepared with atomic precision, which means that their stoichiometries can be ascertained; the properties of these nanoclusters can vary significantly depending on the exact stoichiometry and geometric structure of the system. This leads to important questions such as: What are the general principles that underlie the physical properties of these nanoclusters? Do these principles hold for all systems? What properties can be "tuned" by varying the size and composition of the system? In this Account, we describe research that has been performed to analyze the electronic structure, linear optical absorption, and excited state dynamics of thiolate-stabilized noble metal nanoclusters...
November 16, 2018: Accounts of Chemical Research
https://read.qxmd.com/read/30443374/crystal-structure-of-di-chlorido-bis-%C3%AE-2-meth-oxy-6-methyl-imino-meth-yl-phenolato-2-meth-oxy-6-methyl-imino-meth-yl-phenolato-cadmium-ii-cobalt-iii-monohydrate
#19
Olga Yu Vassilyeva, Katerina V Kasyanova, Vladimir N Kokozay, Brian W Skelton
The title compound, [CoCd(C9 H10 NO2 )3 Cl2 ]·H2 O, is a solvatomorph of the corresponding hemihydrate recently published by us [Nesterova et al. (2018 ▸). Appl. Cat. A , 560 , 171-184]. The current structure reveals different cell parameters and space group compared with the published one while both are monoclinic with almost the same cell volume. The title compound is formed of discrete neutral dinuclear mol-ecules with no crystallographically imposed symmetry and water mol-ecules of crystallization. The overall geometry about the cobalt(III) ion is octa-hedral with an N3 O3 environment; each ligand acts as a meridional ONO donor...
November 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
https://read.qxmd.com/read/30419169/fully-coupled-quantum-treatment-of-nanoconfined-systems-a-water-molecule-inside-a-fullerene-c-60
#20
Álvaro Valdés, Orlando Carrillo-Bohórquez, Rita Prosmiti
We implemented a systematic procedure for treating the quantal rotations by including all translational and vibrational degrees of freedom for any triatomic bent molecule in any embedded or confined environment, within the MCTDH framework. Fully coupled quantum treatments were employed to investigate unconventional properties in nanoconfined molecular systems. In this way, we facilitate a complete theoretical analysis of the underlying dynamics that enables us to compute the energy levels and the nuclear spin isomers of a single water molecule trapped in a C60 fullerene cage...
November 20, 2018: Journal of Chemical Theory and Computation
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