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Attraction symmetry

Chun Li Liu, Qiu Ying Huang, Xiang Ru Meng
The synthesis of coordination polymers or metal-organic frameworks (MOFs) has attracted considerable interest owing to the interesting structures and potential applications of these compounds. It is still a challenge to predict the exact structures and compositions of the final products. A new one-dimensional coordination polymer, catena-poly[[[bis{1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole-κN(3)}zinc(II)]-μ-hexane-1,6-dicarboxylato-κ(4)O(1),O(1'):O(6),O(6')] monohydrate], {[Zn(C6H8O4)(C9H8N6)2]·H2O}n, has been synthesized by the reaction of Zn(Ac)2 (Ac is acetate) with 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) and adipic acid (H2adi) at room temperature...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
G D Ower, J Hunt, S K Sakaluk
Although the strength and form of sexual selection on song in male crickets have been studied extensively, few studies have examined selection on the morphological structures that underlie variation in males' song, particularly in wild populations. Geometric morphometric techniques were used to measure sexual selection on the shape, size and symmetry of both top and bottom tegmina in wild populations of sagebrush crickets, a species in which nuptial feeding by females imposes an unambiguous phenotypic marker on males...
November 7, 2016: Journal of Evolutionary Biology
Bin-Bin Wang, Yong-Chang Han, Shu-Lin Cong
The role of sharp avoided crossings (SACs) in a short hyper-radial range R≤ 50 a.u. in the calculation of recombination for a cold (4)He3 system is investigated in the adiabatic hyperspherical representation by "turning off and on" the relevant nonadiabatic couplings. The influence of SACs on the recombination is related with the channels of the system and with the scattering energy. For J(Π) = 0(+) symmetry, the two-body recombination channel has an attractive potential well, which makes radial wave functions of both two-body recombination channel and three-body continuum channels accessible in the short hyper-radial range where SACs are located...
November 28, 2016: Journal of Chemical Physics
Jan Luxa, Yong Wang, Zdenek Sofer, Martin Pumera
A(III) B(VI) chalcogenides are an interesting group of layered semiconductors with several attractive properties, such as tunable band gaps and the formation of solid solutions. Unlike the typically sandwiched structure of transition-metal dichalcogenides, A(III) B(VI) layered chalcogenides with hexagonal symmetry are stacked through the X-M-M-X motif, in which M is gallium and indium, and X is sulfur, selenium, and tellurium. In view of the inadequate study of the electrochemical properties and great interest in layered materials towards energy-related research, herein the inherent electrochemistry of GaS, GaSe, GaTe, and InSe has been studied, as well as the exploration of their potential as hydrogen evolution reaction (HER) electrocatalysts...
November 16, 2016: Chemistry: a European Journal
Dhiraj R Sikwal, Rahul S Kalhapure, Thirumala Govender
In recent years, a new class of dendrimer, known as Janus dendrimers (JDs), has attracted much attention due to their different structures and properties to the conventional symmetric forms. The broken symmetry of JDs offers the opportunity to form complex self-assembled materials, and presents new sets of properties that are presently inconceivable for homogeneous or symmetrical dendrimers. Due to their unique features, JDs have a promising future in pharmaceutical and biomedical fields, as seen from the recent interest in their application in conjugating multiple drugs and targeting moieties, forming supramolecular hydrogels, enabling micellar delivery systems, and preparing nano-vesicles, known as dendrimersomes, for drug encapsulation...
November 15, 2016: European Journal of Pharmaceutical Sciences
Daniel Morphew, Dwaipayan Chakrabarti
Enclosed three-dimensional structures with hollow interiors have been attractive targets for the self-assembly of building blocks across different length scales. Colloidal self-assembly, in particular, has enormous potential as a bottom-up means of structure fabrication exploiting a priori designed building blocks because of the scope for tuning interparticle interactions. Here we use computer simulation study to demonstrate the self-assembly of designer charge-stabilised colloidal magnetic particles into a series of supracolloidal polyhedra, each displaying a remarkable two-level structural hierarchy...
November 18, 2016: Soft Matter
Mukesh Kumar Singh, Gopalan Rajaraman
Ab initio calculations performed on a series of lanthanide encapsulated fullerenes reveal {DyOSc}@C82 to be one of the best host-guest pairs to offer a barrier height exceeding 1400 cm(-1). The high-symmetry environment preserved inside the cage quenches the QTM effects up to third-excited states leading to very larger barrier heights and this opens up a new possibility of obtaining attractive SMMs based on lanthanide based endohedral metallo-fullerenes (EMFs).
November 17, 2016: Chemical Communications: Chem Comm
Chuanyi Lu, Daomu Zhao
An analytical expression for the elements of the cross-spectral density matrix of electromagnetic multi-Gaussian Schell-model beams with astigmatic aberration propagating through the turbulent ocean is derived. We investigate the statistical characteristics of the beams on propagation in great detail. It is found that, due to astigmatism, the circular symmetry of such beams suffers a certain degree of damage in the near field. In addition, astigmatism also destroys the attractive far-field flat profiles in free space...
October 10, 2016: Applied Optics
Xiaobo Li, Fangfang Cui, Qingliang Feng, Gang Wang, Xiaosa Xu, Juanxia Wu, Nannan Mao, Xing Liang, Zhongyue Zhang, Jin Zhang, Hua Xu
As an anisotropic 2D layered material, rhenium disulfide (ReS2) has attracted much attention because of its unusual properties and promising applications in electronic and optoelectronic devices. However, the low lattice symmetry and interlayer decoupling of ReS2 make asymmetric growth and out-of-plane growth occur quite easily; therefore, thick flake, dendritic and flower-like structures of ReS2 have mostly been obtained previously. Here, we report on an approach based on space-confined epitaxial growth for the controlled synthesis of ReS2 films...
December 7, 2016: Nanoscale
Seema Pande, Wei Huang, Nan Shao, Lei-Ming Wang, Navneet Singh Khetrapal, Wai-Ning Mei, Tian Jian, Lai-Sheng Wang, Xiao Cheng Zeng
Gold nanoclusters have attracted great attentions in the past decade due to their remarkable size-dependent electronic, optical, and catalytic properties. However, the structures of large gold clusters are still not well known because of the challenges in global structural searches. Here we report a joint photoelectron spectroscopy (PES) and theoretical study of the structural evolution of negatively-charged core-shell gold nanoclusters (Aun-) for n = 42 to 50. Photoelectron spectra of size-selected Aun- clusters are well resolved with distinct spectral features, suggesting a dominating structural type...
October 30, 2016: ACS Nano
Balaram Pradhan, V M Vaisakh, Geetha G Nair, D S Shankar Rao, S Krishna Prasad, Achalkumar Ammathnadu Sudhakar
Two series of polycatenars are reported that contain a central thiophene moiety connected to two substituted oxadiazole or thiadiazole units. The number, position, and length of the peripheral chains connected to these molecules were varied. The oxadiazole-based polycatenars exhibited columnar phases with rectangular and hexagonal or oblique symmetry, whereas the thiadiazole-based polycatenars exhibited columnar phases with rectangular and/or hexagonal symmetry. All of the compounds exhibited bright emission in the solution and thin-film states...
October 28, 2016: Chemistry: a European Journal
Nelly Bonifaci, Zhiling Li, Jussi Eloranta, Steven L Fiedler
The interaction potentials of the He(*)(2) excimer, in the a (3)Σu, b (3)Πg, c (3)Σg , and d (3)Σu electronic states with a ground state helium atom are presented. The symmetry of the interaction potentials closely follows the excimer Rydberg electron density with pronounced short-range minima appearing along the nodal planes of the Rydberg orbital. In such cases, a combination of the electrostatic short-range attraction combined with Pauli repulsion leads to the appearance of unusual long-range maxima in the potentials...
October 26, 2016: Journal of Physical Chemistry. A
Christina Bagwill, Christa Anderson, Elizabeth Sullivan, Varun Manohara, Prithvi Murthy, Charles C Kirkpatrick, Apryll M Stalcup, Michael Adam Lewis
A computational study aimed at accurately predicting the strength of the anion-π binding of substituted benzenes is presented. The anion-π binding energies (Ebind) of 37 substituted benzenes, and the parent benzene, with chloride or bromide were investigated at the MP2(full)/6-311++G** level of theory. In addition, energy decomposition analysis was performed on 27 selected chloride-arene complexes via Symmetry Adapted Perturbation Theory (SAPT), using the SAPT2+ approach. Initial efforts aimed to correlate the anion-π Ebind values with the sum of the Hammett constants σp (Σσp) or σm (Σσm), as done by others...
October 25, 2016: Journal of Physical Chemistry. A
Laurent Pedesseau, Daniel Sapori, Boubacar Traore, Roberto Robles, Hong-Hua Fang, Maria Antonietta Loi, Hsinhan Tsai, Wanyi Nie, Jean-Christophe Blancon, Amanda Neukirch, Sergei Tretiak, Aditya D Mohite, Claudine Katan, Jacky Even, Mikaël Kepenekian
Layered halide hybrid organic-inorganic perovskites (HOP) have been the subject of intense investigation before the rise of three-dimensional (3D) HOP and their impressive performance in solar cells. Recently, layered HOP have also been proposed as attractive alternatives for photostable solar cells and revisited for light-emitting devices. In this review, we combine classical solid-state physics concepts with simulation tools based on density functional theory to overview the main features of the optoelectronic properties of layered HOP...
October 24, 2016: ACS Nano
Michael G Sommer, Yvonne Rechkemmer, Lisa Suntrup, Stephan Hohloch, Margarethe van der Meer, Joris van Slageren, Biprajit Sarkar
The azido ligand is widely used in coordination chemistry both as a ligand and as a metal-bound reactant. Its role as a bridge for magnetic exchange coupling has attracted a lot of attention in polynuclear metal complexes. However, only a very limited number of complexes are known in which a single azide anion, particularly in the μ1,1-mode, is the only unsupported connection between two metal centers. We present here a series of copper(ii)-azido complexes with amine anchored, triazole-based tripodal ligands containing varying substituents...
October 21, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Justin K Mogilski, Lisa L M Welling
Sexual dimorphism, symmetry, and coloration in human faces putatively signal information relevant to mate selection and reproduction. Although the independent contributions of these characteristics to judgments of attractiveness are well established, relatively few studies have examined whether individuals prioritize certain features over others. Here, participants (N = 542, 315 female) ranked six sets of facial photographs (3 male, 3 female) by their preference for starting long- and short-term romantic relationships with each person depicted...
October 17, 2016: Human Nature: An Interdisciplinary Biosocial Perspective
Naiyin Yu, Abhijit Ghosh, Michael F Hagan
We use computer simulations and simple theoretical models to analyze the morphologies that result when rod-like particles end-attach onto a curved surface, creating a finite-thickness monolayer aligned with the surface normal. This geometry leads to two forms of frustration, one associated with the incompatibility of hexagonal order on surfaces with Gaussian curvature, and the second reflecting the deformation of a layer with finite thickness on a surface with non-zero mean curvature. We show that the latter effect leads to a faceting mechanism...
October 17, 2016: Soft Matter
Chandan K Mishra, A K Sood, Rajesh Ganapathy
The monomer surface mobility is the single most important parameter that decides the nucleation density and morphology of islands during thin-film growth. During template-assisted surface growth in particular, low surface mobilities can prevent monomers from reaching target sites and this results in a partial to complete loss of nucleation control. Whereas in atomic systems a broad range of surface mobilities can be readily accessed, for colloids, owing to their large size, this window is substantially narrow and therefore imposes severe restrictions in extending template-assisted growth techniques to steer their self-assembly...
October 25, 2016: Proceedings of the National Academy of Sciences of the United States of America
Y Zhang, J J Lee, R G Moore, W Li, M Yi, M Hashimoto, D H Lu, T P Devereaux, D-H Lee, Z-X Shen
Superconductivity originates from pairing of electrons near the Fermi energy. The Fermi surface topology and pairing symmetry are thus two pivotal characteristics of a superconductor. Superconductivity in one monolayer (1 ML) FeSe thin film has attracted great interest recently due to its intriguing interfacial properties and possibly high superconducting transition temperature over 65 K. Here, we report high-resolution measurements of the Fermi surface and superconducting gaps in 1 ML FeSe using angle-resolved photoemission spectroscopy...
September 9, 2016: Physical Review Letters
Elad Shamriz, Nir Dror, Boris A Malomed
We report results of an analysis of the spontaneous symmetry breaking (SSB) in a basic (actually, simplest) model that is capable of producing the SSB phenomenology in a one-dimensional setting. It is based on the Gross-Pitaevskii-nonlinear Schrödinger equation with the cubic self-attractive term and a double-well potential built as an infinitely deep potential box split by a narrow (δ functional) barrier. The barrier's strength ɛ is the single free parameter of the scaled form of the model. It may be implemented in atomic Bose-Einstein condensates and nonlinear optics...
August 2016: Physical Review. E
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