Samuel V. Gallego  Jesus Etxebarria  Luis Elcoro  Emre S. Tasci  J. Manuel Perez-Mato 《Acta Crystallographica. Section A, Foundations and Advances》2019,75(3):438-447

Two new programs, MTENSOR and TENSOR, hosted on the open‐access website known as the Bilbao Crystallographic Server, are presented. The programs provide automatically the symmetry‐adapted form of tensor properties for any magnetic or non‐magnetic point group or space group. The tensor is chosen from a list of 144 known tensor properties gathered from the scientific literature or, alternatively, the user can also build a tensor that possesses an arbitrary intrinsic symmetry. Four different tensor types are considered: equilibrium, transport, optical and nonlinear optical susceptibility tensors. For magnetically ordered structures, special attention is devoted to a detailed discussion of the transformation rules of the tensors under the time‐reversal operation 1′. It is emphasized that for non‐equilibrium properties it is the Onsager theorem, and not the constitutive relationships, that indicates how these tensors transform under 1′. In this way it is not necessary to restrict the validity of Neumann's principle. New Jahn symbols describing the intrinsic symmetry of the tensors are introduced for several transport and optical properties. In the case of some nonlinear optical susceptibilities of practical interest, an intuitive method is proposed based on simple diagrams, which allows easy deduction of the action of 1′ on the susceptibilities. This topic has not received sufficient attention in the literature and, in fact, it is usual to find published results where the symmetry restrictions for such tensors are incomplete.  相似文献   

    

Manuel K. Rausch  Mrudang Mathur  William D. Meador 《GAMM-Mitteilungen》2019,42(3)

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Dr. Nina Erini  Vera Beermann  Martin Gocyla  Manuel Gliech  Dr. Marc Heggen  Dr. Rafal E. Dunin-Borkowski  Prof. Peter Strasser 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6633-6638

Direct ethanol fuel cells are attractive power sources based on a biorenewable, high energy-density fuel. Their efficiency is limited by the lack of active anode materials which catalyze the breaking of the C−C bond coupled to the 12-electron oxidation to CO₂. We report shape-controlled PtNiRh octahedral ethanol oxidation electrocatalysts with excellent activity and previously unachieved low onset potentials as low as 0.1 V vs. RHE, while being highly selective to complete oxidation to CO₂. Our comprehensive characterization and in situ electrochemical ATR studies suggest that the formation of a ternary surface site ensemble around the octahedral Pt₃Ni₁Rh_x nanoparticles plays a crucial mechanistic role for this behavior.  相似文献   

    

Manuel van Gemmeren  Marino Börjesson  Andreu Tortajada  Shang-Zheng Sun  Keisho Okura  Prof. Ruben Martin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6658-6662

A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO₂ is used with dual roles, both facilitating C−OH cleavage and as a C₁ source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand employed.  相似文献   

    

Alexander Carreño  Eduardo Schott  Ximena Zarate  Juan Manuel Manriquez  Juan C. Vega  Miguel Mardones  Alan H. Cowley  Ivonne Chavez  Juan P. Hinestroza  Ramiro Arratia-Perez 《Chemical Papers》2017,71(6):1019-1030

Research in functionalized inorganic supports faces special challenges regarding the inmobilization of organic chains and efficient computational methods for the quantum chemical modeling of coordination compounds. The silylant 3-cloropropyltriethoxysilyl (R1) was anchored over silica gel in anhydrous conditions, in order to react with diethyl Iminodiacetate (DIDA) to obtain modified silica gel (R2), which was hydrolized in basic conditions previously synthesized and characterized by S _BET, TGA and FTIR spectroscopy to obtain iminodiacetic acid groups IDA to prepare an modified inorganic support (R3) that is able to get hands on metals from the first transition series such as copper and nickel. The obtained experimental values showed that the functionalized grade of R3 corresponds to 0.1598 mmol of the nitrogen indicated that the adsorbed Cu(II) or Ni(II) have the stoichiometry for both cation of 1:1. Based on this relation, the three different structures were proposed to carry out the computational studies using density functional theory (DFT) in its LDA and PW91 with the TZP slater type basis set. The primary coordination sphere of copper(II) or nickel (II) ion in R3 are optimized, structural parameters are calculated, vibrational bands are assigned and energy gaps of frontier orbital (HOMO–LUMO) have been calculated. The calculated results reproduced the experimental data with good agreement. An energy decomposition analysis (EDA) of the different models proposed here was performed and suggest a 1:1 coordination form.  相似文献   

    

M. Sc. Elena Kusevska  Dr. M. Merced Montero-Campillo  Prof. Otilia Mó  Prof. Manuel Yáñez 《Angewandte Chemie (International ed. in English)》2017,56(24):6788-6792

Owing to its versatility in synthetic chemistry, TPB (tris[2-diisopropylphospino)phenyl]borane) is a very important frustrated Lewis Pair. The unusual stability of the neutral radical (TPB)Cu has been related to the presence of a one-electron B−Cu bond. Herein we show, through the use of different computational chemistry methods, that the existence and nature of this kind of A⋅⋅⋅M bond (A=donor atom, M=transition metal) depends on the surrounding chemical structure, and can be genuine one-electron sigma bonds only if appropriate metal ligands (Y), able to trap the charge in the desired region, are chosen. This ability is modulated by the subtle balance between the electronegativity of the different atoms along the A⋅⋅⋅M⋅⋅⋅Y bond paths. Most importantly, contrary to many TPB complexes in which boron acts as a Lewis acid, in one-electron-bond-containing structures boron behaves as a Lewis base.  相似文献   

    

Md Ashfaqul Bari  Cemil Akbulut  Manuel Münsch  Antonio Delgado 《PAMM》2018,18(1)

Numerical simulation of two‐phase flows using Volume of Fluid (VOF) method is known be to susceptible to parasitic currents, which arises due to erroneous interface curvature calculation to model the surface tension force. The interface curvature calculation scheme in OpenFoam has been modified according to the Sharp Surface Force (SSF) which reduced parasitic currents magnitude significantly. Alongside SSF method the Continuous Species Transfer (CST) equation is implemented in OpenFOAM 4.1 to simulate mass transfer from an Oxygen bubble to the surrounding stagnant water‐glycerol solution under micro‐gravity environment.  相似文献   

    

Héctor Manuel Moya-Cessa 《Contemporary Physics》2018,59(1)

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Plasma physics – an introduction to laboratory,space, and fusion plasmas, 2nd edition     

Manuel Vogel 《Contemporary Physics》2018,59(3):329-330

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Atoms,mechanics, and probability: Ludwig Boltzmann’s statistico-mechanical writings – an exegesis,by O. Darrigol     

Manuel Vogel 《Contemporary Physics》2018,59(2):210-211

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