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Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title heteroleptic cuprous complex, [2,2′‐bis(diphenylphosphanyl)‐1,1′‐binaphthyl‐κ2P,P′](2‐phenylpyridine‐κN)copper(I) hexafluoridophosphate, rac‐[Cu(C44H32P2)(C11H9N)]PF6, conventionally abbreviated rac‐[Cu(BINAP)(2‐PhPy)]PF6 (I), where BINAP and 2‐PhPy represent 2,2′‐bis(diphenylphosphanyl)‐1,1′‐binaphthyl and 2‐phenylpyridine, respectively, is described. In this complex, the asymmetric unit consists of a hexafluoridophosphate anion and a heteroleptic cuprous complex cation, in which the cuprous centre in a CuP2N coordination triangle is coordinated by two P atoms from the BINAP ligand and by one N atom from the 2‐PhPy ligand. Time‐dependent density functional theory (TD–DFT) calculations show that the UV–Vis absorption of I should be attributed to ligand‐to‐ligand charge transfer (LLCT) characteristic excited states. It was also found that the paper‐based film of this complex exhibited obvious luminescence light‐up sensing for pyridine. [ABSTRACT FROM AUTHOR]

In this paper, the atomic configuration, electronic structure, and work of adhesion for TiN(111)//B2‐NiTi(110) and TiN(111)//B19′‐NiTi(010) interfaces were investigated by first‐principles calculations based on density functional theory (DFT), which aim to provide a theoretical guidance for analyzing the service reliability of TiN films modified NiTi alloy devices. The results of this paper indicated that a hollow‐site stacking structure was formed on the interface when Ti and N were the terminal atoms on two sides. Such interfaces demonstrated a stronger bonding performance and a more stable structure than that with Ni and Ti as the terminal atoms. The work of adhesion of the TiN(111)//B19′‐NiTi(010) interface was 17.47 J/m2, which is greater than the work of fracture of TiN(111) (6.73 J/m2), whereas the work of adhesion of the TiN(111)//B2‐NiTi(110) interface was found to reach 5.49 J/m2, which is lower than the work of fracture of TiN(111). The models of the work of adhesion between the two interfaces indicate that there are significant bond strength changes in the TiN/NiTi interface, when the NiTi substrate undergoes martensitic transformation. The results of this paper contribute significantly to the service reliability analysis of TiN films coated on NiTi alloy devices. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the boundedness of mixed Journé's class operators on weighted multi‐parameter mixed Hardy spaces via atoms decomposition. Moreover, we give a specific singular integral operator in mixed Journé's class which has better properties. [ABSTRACT FROM AUTHOR]

The X‐ray constrained wavefunction (XCW) procedure for obtaining an experimentally reconstructed wavefunction from X‐ray diffraction data is reviewed. The two‐center probability distribution model used to perform nuclear‐position averaging in the original paper [Grimwood & Jayatilaka (2001). Acta Cryst. A57, 87–100] is carefully distinguished from the newer one‐center probability distribution model. In the one‐center model, Hirshfeld atoms are used, and the Hirshfeld atom based X‐ray constrained wavefunction (HA‐XCW) procedure is described for the first time, as well as its efficient implementation. In this context, the definition of the related X‐ray wavefunction refinement (XWR) method is refined. The key halting problem for the XCW method – the procedure by which one determines when overfitting has occurred – is named and work on it reviewed. [ABSTRACT FROM AUTHOR]

Nanozymes have received extensive attention in the fields of sensing and detection, medical therapy, industry, and agriculture thanks to the combination of the catalytic properties of natural enzymes and the physicochemical properties of nanomaterials, coupled with superior stability and ease of preparation. Despite the promise of nanozymes, conventional nanozymes are constrained by their oversized size and low catalytic capacity in sophisticated practical application environments. single‐atom nanozymes (SAzymes) were characterized as nanozymes with high catalytic efficiency by uniformly distributed single atoms as catalysis sites, thus effectively addressing the defects of conventional nanozymes. This paper reviews the activity improvement scheme and catalytic mechanism of SAzymes and highlights the latest research progress of SAzymes in the fields of biomedical sensing and therapy. Eventually, the challenges and future directions of SAzymes are discussed in this paper. [ABSTRACT FROM AUTHOR]

Atom transfer radical addition (ATRA) of halogenated compounds with alkenes is well established but primary alkyl chlorides are understudied because of the difficult C−Cl bond activation. In this paper, we show that TONs of 61 can be achieved in the ATRA of ethyl chloroacetate onto styrene with [Cp*Ru(Cl)2(PPh3)] and 1,1′‐azobis(cyclohexanecarbonitrile) (ACHN) as a radical initiator, representing a three‐fold improvement compared to previous reports. New catalyst precursors of the type [Cp*Ru(Cl)2(PR3)] were synthesized and tested (R=Me, Et, Cy, Ph, p‐CF3C6H4 and p‐MeOC6H4). The kinetic reaction profiles were studied using in situ ATR−FTIR spectroscopy. Among these complexes, [Cp*Ru(Cl)2(PPh3)] gave the best yields while [Cp*Ru(Cl)2(PMe3)] showed the highest rate. While rates correlate with redox potentials (electronics), our investigation reveals that substrate sterics are important for the overall yield. Density functional theory calculations suggest an open‐shell singlet pathway, where polymerization is kinetically disfavored, explaining the selectivity towards ATRA products. [ABSTRACT FROM AUTHOR]

In this paper, conventional phonon blockade (CPNB) and conventional photon blockade (CPTB) effects, as well as unconventional phonon blockade (UPB) effects, are studied in an optomechanical system with nonlinear interaction between the cavity frequency and the square of the mechanical displacement driven by an external field, where a two‐level atom couples with the mechanical mode and a microwave driving field pumps cavity mode. The second‐order correlation function is analytically calculated, which is in good agreement with the numerical simulation given by the master equation. With energy‐level diagram, the atom‐mechanical mode coupling is found to induces the degeneracy splitting of the states and give the optimal conditions for CPNB and CPTB in this system. With the origin of UPB, the optimal conditions are derived and it is found that the realization of UPB is determined by the two couplings of the cavity and atom with respect to the mechanical mode. Moreover, some discussions on the experimental implementation in this quadratically coupled optomechanical system are presented. This study provides a possible way for realizing single‐photon nonlinearity and can extend the applications of optomechanical systems in the field of quantum optics. [ABSTRACT FROM AUTHOR]

Rationale: The observed isotope distribution is an important attribute for the identification of peptides and proteins in mass spectrometry-based proteomics. Sulphur atoms have a very distinctive elemental isotope definition, and therefore, the presence of sulphur atoms has a substantial effect on the isotope distribution of biomolecules. Hence, knowledge of the number of sulphur atoms can improve the identification of peptides and proteins. Methods: In this paper, we conducted a theoretical investigation on the isotope properties of sulphur-containing peptides. We proposed a gradient boosting approach to predict the number of sulphur atoms based on the aggregated isotope distribution. We compared prediction accuracy and assessed the predictive power of the features using the mass and isotope abundance information from the first three, five and eight aggregated isotope peaks. Results: Mass features alone are not sufficient to accurately predict the number of sulphur atoms. However, we reach near-perfect prediction when we include isotope abundance features. The abundance ratios of the eighth and the seventh, the fifth and the fourth, and the third and the second aggregated isotope peaks are the most important abundance features. The mass difference between the eighth, the fifth or the third aggregated isotope peaks and the monoisotopic peak are the most predictive mass features. Conclusions: Based on the validation analysis it can be concluded that the prediction of the number of sulphur atoms based on the isotope profile fails, because the isotope ratios are not measured accurately. These results indicate that it is valuable for future instrument developments to focus more on improving spectral accuracy to measure peak intensities of higher-order isotope peaks more accurately. [ABSTRACT FROM AUTHOR]

In this paper, a robust and accurate protocol is proposed to realize nondestructive parity measurement of artificial atoms using a superconducting resonator and homodyne measurement. With the help of an additional microwave driving field, the cavity field evolves into a coherent state or remains in a vacuum state according to the parity of the atoms. Consequently, the parity information of atoms can be read out by a homodyne measurement on the cavity. Parity information can be obtained without destroying the original state of the system, which means that the state can be further applied to other quantum information processing tasks after a parity measurement. The numerical simulation results show that the protocol is robust against systematic error, random noise, and decoherence. Therefore, this protocol can provide a feasible viewpoint for nondestructive parity measurement. [ABSTRACT FROM AUTHOR]

Midlatitude ionosonde observations show that there is a sporadic E (Es) diurnal cycle that starts in higher altitudes at sunrise. This property is labeled as the "Sporadic E sunrise effect." Given that sporadic E layers are composed of metal ions, the sunrise effect implies that metal atom solar photoionization could play a role in the diurnal variability of sporadic E occurrence. This possibility is endorsed by Arecibo's incoherent scatter radar observations, showing that weak ion layers at lowest E and uppermost D region heights appear at sunrise to live during the daytime, apparently coming out of nighttime metal atom mesospheric layers. The solar photoionization of metal atoms increases the abundance of metal ions available for Es layer generation during the daytime, whereas this effect is absent at nighttime. This can explain why sporadic E layers start or intensify at sunrise all year round and why Es activity maximizes during sunlit hours, as has been reported in many ionosonde and satellite radio occultation studies. The significance of metal atom solar photoionization on the regular diurnal variation of Es went unnoticed, despite existing evidence for a long time. The present paper provides a base for a better physical understanding of the pronounced 24-hr periodicity in Es layer intensity and places a step toward the improvement of simulation models for the predictions of sporadic E layer characteristics. [ABSTRACT FROM AUTHOR]

Chaos is important in nonlinear science and promotes the development of fundamental studies, such as neural networks, extreme event statistics, and electron transport. In this paper, a theoretical scheme for generating dynamical chaos in a Fabry–Perot cavity with two‐level atoms is investigated. Through the injection of atoms, controllable chaos of the cavity and mechanical oscillator is achieved simultaneously by the external laser field. The trajectory and the maximal Lyapunov exponent that characterize the properties of the chaos could be optimized by adjusting the coupling constant, driving field, injection of atoms, the frequency of the cavity, and the frequency of the mechanical oscillator. This study provides a new idea to manipulate the cavity and mechanical chaos assisted by two level atoms. It is hoped that the results presented can benefit controllable chaos generation and its applications. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of two two‐level atoms, which simultaneously couple to a quasi‐1D waveguide with rectangular cross section. The waveguide modes serve as environment, which induces the interaction and collective dissipation between the two distant atoms. When both of the two atoms are located in the middle of the waveguide, a retardation effect is observed, which can be broken by moving one of the atoms away from the center of the waveguide. To preserve the complete dissipation of the system via dark state mechanism, a scheme where the connection of the atoms is perpendicular to the axis of the waveguide is proposed. [ABSTRACT FROM AUTHOR]

Nano‐carbon oxygen reduction reaction (ORR) catalyst having a large N atoms content derived from biomass has been widely studied recently in fuel cells. In this paper, yuba of high‐protein (wt. 53 %) was employed as precursor to fabricate N self‐doped porous carbon ORR electrocatalysts with high N content. In terms of ORR performance, Y‐850 exhibited the optimal electrocatalytic activity among all the samples at different pyrolysis temperatures, which is comparable that of commercial 20 % Pt/C. The prominent ORR characteristic of Y‐850 is mainly contributed by its high N content, especially high graphitic‐N content. In order to further improve its ORR performance, ball‐milling was conducted on Y‐850 before and after pyrolysis. The results indicate that an appropriate ball‐milling before pyrolysis can effectively increase the limited current density of ORR. [ABSTRACT FROM AUTHOR]

Nitrogenase is the enzyme that converts N2 to NH3 under ambient conditions. The chemical mechanism of this catalysis at the active site FeMo‐co [Fe7S9CMo(homocitrate)] is unknown. An obligatory co‐product is H2, while exogenous H2 is a competitive inhibitor. Isotopic substitution using exogenous D2 revealed the N2‐dependent reaction D2+2H++2e−→2HD (the 'HD reaction'), together with a collection of additional experimental characteristics and requirements. This paper describes a detailed mechanism for the HD reaction, developed and elaborated using density functional simulations with a 486‐atom model of the active site and surrounding protein. First D2 binds at one Fe atom (endo‐Fe6 coordination position), where it is flanked by H−Fe6 (exo position) and H−Fe2 (endo position). Then there is synchronous transfer of these two H atoms to bound D2, forming one HD bound to Fe2 and a second HD bound to Fe6. These two HD dissociate sequentially. The final phase is recovery of the two flanking H atoms. These H atoms are generated, sequentially, by translocation of a proton from the protein surface to S3B of FeMo‐co and combination with introduced electrons. The first H atom migrates from S3B to exo‐Fe6 and the second from S3B to endo‐Fe2. Reaction energies and kinetic barriers are reported for all steps. This mechanism accounts for the experimental data: (a) stoichiometry; (b) the N2‐dependence results from promotional N2 bound at exo‐Fe2; (c) different N2 binding Km for the HD reaction and the NH3 formation reaction results from involvement of two different sites; (d) inhibition by CO; (e) the non‐occurrence of 2HD→H2+D2 results from the synchronicity of the two transfers of H to D2; (f) inhibition of HD production at high pN2 is by competitive binding of N2 at endo‐Fe6; (g) the non‐leakage of D to solvent follows from the hydrophobic environment and irreversibility of proton introduction. [ABSTRACT FROM AUTHOR]

This paper describes the global and local analysis of atomic displacement parameters (ADPs) of macromolecules in X‐ray crystallography. The distribution of ADPs is shown to follow the shifted inverse‐gamma distribution or a mixture of these distributions. The mixture parameters are estimated using the expectation–maximization algorithm. In addition, a method for the resolution‐ and individual ADP‐dependent local analysis of neighbouring atoms has been designed. This method facilitates the detection of mismodelled atoms, heavy‐metal atoms and disordered and/or incorrectly modelled ligands. Both global and local analyses can be used to detect errors in atomic models, thus helping in the (re)building, refinement and validation of macromolecular structures. This method can also serve as an additional validation tool during PDB deposition. [ABSTRACT FROM AUTHOR]

The relativistic effects have been widely reported to affect the chemical and physical properties of the heavy elements such as lanthanides (57≤z≤71), actinides (89≤z≤103), and transactinides (z≥104). This effect is definitely weakened by reducing the atomic number z in lighter elements such as hydrogen‐like atoms (HLAs). The aim of present paper is to investigate the relativistic effects of electron motion in Bohr orbits on the chemical and physical properties of HLAs. The theoretical model is based on the Heisenberg (rather than Schrodinger) picture where the relativistic vibrational Hamiltonian (RVH) Hvibrel is expanded as a power series of harmonic oscillator Hamiltonian H0 for the first time. By applying the first‐order RVH (correct to H0) to the Heisenberg equation, a pair of coupled equations is obtained for the relativistic position and linear momentum of electron. A simple comparison of the first‐order relativistic and nonrelativistic equations reveals that the relativistic natural frequency of an HLA (like entropy) is slowly raised by increasing z beyond z≈20. In general, RVH plays a fundamental role because it specifies the temporal relativistic variations of position, velocity, and linear momentum of the oscillating electron. The results are finally verified by demonstrating energy conservation. [ABSTRACT FROM AUTHOR]

In 2010 we energy-minimized 225 high-quality single-crystal (SX) structures with dispersion-corrected density functional theory (DFT-D) to establish a quantitative benchmark. For the current paper, 215 organic crystal structures determined from X-ray powder diffraction (XRPD) data and published in an IUCr journal were energy-minimized with DFT-D and compared to the SX benchmark. The on average slightly less accurate atomic coordinates of XRPD structures do lead to systematically higher root mean square Cartesian displacement (RMSCD) values upon energy minimization than for SX structures, but the RMSCD value is still a good indicator for the detection of structures that deserve a closer look. The upper RMSCD limit for a correct structure must be increased from 0.25 Å for SX structures to 0.35 Å for XRPD structures; the grey area must be extended from 0.30 to 0.40 Å. Based on the energy minimizations, three structures are re-refined to give more precise atomic coordinates. For six structures our calculations provide the missing positions for the H atoms, for five structures they provide corrected positions for some H atoms. Seven crystal structures showed a minor error for a non-H atom. For five structures the energy minimizations suggest a higher space-group symmetry. For the 225 SX structures, the only deviations observed upon energy minimization were three minor H-atom related issues. Preferred orientation is the most important cause of problems. A preferred-orientation correction is the only correction where the experimental data are modified to fit the model. We conclude that molecular crystal structures determined from powder diffraction data that are published in IUCr journals are of high quality, with less than 4% containing an error in a non-H atom. [ABSTRACT FROM AUTHOR]

This paper analyzes a common‐value, first‐price auction with state‐dependent participation. The number of bidders, which is unobservable to them, depends on the true value. For participation patterns with many bidders in each state, the bidding equilibrium may be of a "pooling" type—with high probability, the winning bid is the same across states and is below the ex ante expected value—or of a "partially revealing" type—with no significant atoms in the winning bid distribution and an expected winning bid increasing in the true value. Which of these forms will arise is determined by the likelihood ratio at the top of the signal distribution and the participation across states. We fully characterize this relation and show how the participation pattern determines the extent of information aggregation by the price. [ABSTRACT FROM AUTHOR]

Interaction of atoms with twisted light is the subject of intense experimental and theoretical investigation. In almost all studies, the atom is viewed as a localized probe of the twisted light field. However, as argued in this paper, conceptually novel effects will arise if light‐atom interaction is studied in the double‐twisted regime with delocalized atoms, that is, either via twisted light absorption by atom vortex beam, or via two‐twisted‐photon spectroscopy of atoms in a non‐vortex but delocalized state. Even for monochromatic twisted photons and for an infinitely narrow line, absorption will occur over a finite range of detuning. Inside this range, a rapidly varying absorption probability is predicted, revealing interference fringes induced by two distinct paths leading to the same final state. The number, location, height, and contrast of these fringes can give additional information on the excitation process which would not be accessible in usual spectroscopic settings. Visibility of the predicted effects will be enhanced at the future Gamma factory thanks to the large momenta of ions. [ABSTRACT FROM AUTHOR]

Graphyne (GY) is an allotrope composed of sp and sp2 hybridized carbon atoms. In this paper, the adsorption performance of Ti‐modified GY (Ti‐GY) system on the adsorption of CH4 molecules is studied based on first principles. The study found that the most stable adsorption site for Ti atoms is the six‐membered carbon ring pore site. There is a strong ionic interaction between the two, and the Ti‐GY system structure remains stable during the adsorption of CH4 molecules. A single Ti‐modified GY can adsorb 7 CH4 molecules on one side, and the adsorption structure is stratified, with average adsorption energy of −0.298 eV, and an adsorption capacity of 0.369 g g−1; two Ti‐modified GY adsorbs 14 CH4 molecules on double‐sided, the average adsorption energy is about −0.300 eV, and the adsorption capacity reaches 0.484 g g−1. The first layer of CH4 molecules is adsorbed, which is mainly affected by the Ti atoms. There is a strong Coulomb interaction between it and Ti. With the increase of CH4 molecules, the adsorption energy decreases; While the second layer of CH4 molecules is due to the distance Ti atoms are far away, At this time, the interaction between the CH4 molecules and the substrate is mainly the electrostatic interaction between the positively charged CH4 molecules and the negatively charged GY and the van der Waals interaction between the CH4 molecules. The adsorption performance of CH4 molecules is closely related to the pore size of the two‐dimensional adsorbent. When the pore size is small, the interaction between molecules is enhanced and the average adsorption energy is larger. On the contrary, the larger the pore size, the higher the adsorption capacity. [ABSTRACT FROM AUTHOR]

Atomic resolution X‐ray holography can be realized by using the atoms of the sample as inside sources or inside detectors. However, until now there were only very few experiments in which the atoms played the role of inside sources. The reason is twofold: (i) technically, inside‐detector experiments are much easier and faster; (ii) by using atoms as inside detectors one can measure holograms at many energies on the same sample, which helps the reconstruction. This paper shows that, using new technical developments, inside‐source holograms can be taken much faster than inside‐detector holograms and, by applying a sophisticated evaluation method, high‐quality reconstruction from a single‐energy hologram can also be obtained. An experimental demonstration of a fast inside‐source holography measurement and structure reconstruction is presented. This type of measurement provides a route to single‐pulse structure determination at X‐ray free‐electron lasers allowing strongly non‐ambient conditions. [ABSTRACT FROM AUTHOR]

The minimum atomic parameters/Moscow–Aachen–Paris (MAP) basis sets—reintroduced in the previous paper—are analyzed with respect to spatial features as orbital shape, possible fits to alternative orbital sets (numerical or quasi‐numerical orbitals, nodeless Slater orbitals), respect of Kato's condition and radial distribution of energy components. For comparing orbital spaces the Frobenius angle between the orbital subspaces they span is introduced as numerical tool. It is shown that the electronic density of the MAP states is depleted around the nucleus with respect to the other orbital sets. Despite this, the similarity between the respective subspaces in all cases (except a unique case of the Pd atom) as measured by the cosine of the Frobenius angle amounts above 0.96 for all atoms. Deviations from the perfect value of Kato's condition amounts systematically to 0.3 and 0.5 for all elements considered. Integrating one‐electron energy contributions from r = ∞ to a finite radius, MAP and Bunge orbitals show about the same values, but for the inner region governed by the polynomial oscillations. [ABSTRACT FROM AUTHOR]

This paper presents a brief summary of the difficulty that resides in the definition of the elusive concept of local chemical hardness. We argue that a definition of local hardness should be useful to a reactivity principle and not just as a mere definition. We then continue with a formal discussion about the benefits and difficulties of using the Fukui potential, which is interpreted as an alchemical derivative (alchemical hardness), as descriptor of local hardness of molecules. Computational evidence shows that the alchemical hardness is at least as good a descriptor as the combination of other two well‐stabilized descriptors of local hardness, such as the Fukui function and grand canonical local hardness. Although our results are auspicious for the alchemical hardness as descriptor of local hardness, we finish by calling the attention of the community on the importance of discussing the raison d'être of a local hardness function and its main characteristics. We suggest that an axiomatic construction of local hardness could be they way of constructing a local hardness which is both useful and free of arbitrariness. [ABSTRACT FROM AUTHOR]

Atom Transfer Radical Polymerization (ATRP) is the most powerful and most employed technology of Controlled Radical Polymerization (CRP) to produce polymers with well‐defined architecture, that is, composition, topology, and functionality. Several hundreds of papers are published every year on ATRP processes, mainly based on empiric experimental procedures. Electrochemistry powerfully entered in the field of ATRP about 10 years ago, providing important contributions both to the further development of the process and to a better understanding of its mechanism. Five main issues took advantage of electrochemistry and/or its synergism with ATRP: i) understanding the mechanism of ATRP activation; ii) determination of thermodynamic parameters; iii) determination of activation and deactivation rate constants; iv) the SARA ATRP vs SET‐LRP dispute: the role of Cu0; v) electrochemically‐mediated ATRP. [ABSTRACT FROM AUTHOR]

The interrelation between the configurational lability of nitrogen and sulfur atoms within the –NH–SO2 group of some thiazine sulfonamides is discussed. We have found that the compounds of the above series can crystallize as various diastereomers by the nitrogen atom, the relative configuration of the nitrogen atom determining the relative supramolecular configuration of the newly formed chiral sulfur atom. The paper presents a stereochemical transformation, which we have called "double crystallization‐induced diastereomerization." [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) is a ubiquitous network that assists the system to monitor and organize the world by processing, collection, and analysis of produced data by IoT nodes. The IoT is susceptible to numerous attacks, wherein the sinkhole attack is the most destructive one, which affects the communication amongst network devices. The security of the IoT is affected due to the lack of dynamic network topology, centralized control, and network communications, so that the trust‐based routing is important. The conventional trust‐based routing strategies are ineffective to offer protection against attack and thus, trust management remains a major challenge in routing. This paper proposes a novel technique namely Atom Search Sunflower Optimization (ASSFO) for providing trust‐based routing in IoT network. The proposed ASSFO is designed by incorporating Sunflower Optimization (SFO) in Atom Search Optimization (ASO). The method utilizes several trust factors for determining and isolating attacks while optimizing the performance of the network. The trust factors considered in the method include indirect trust, recent trust, integrity factor, direct trust, and availability factor. Moreover, the trusted nodes are selected using the trust factor and further used for secure routing using the proposed ASSFO algorithm. The proposed ASSFO outperformed other methods with maximal energy of 0.908, maximal trust of 0.845, maximal PDR of 0.907, and maximal throughput of 0.909. [ABSTRACT FROM AUTHOR]

Selecting active elements for filler metal is very important in soldering of ZrO2 ceramics. In this paper, the effects of Ti, Al, Cu, and Ag active elements on the bonding strength and electronic structures of soldered β‐Sn(100)/ZrO2(111) interface were studied via the method of first principle calculation. The work of adhesion (Wad) results show that the O2‐terminated interface is more stable than other kinds of interfaces. Then, the atoms of Ti, Al, Cu, and Ag were doped into the interface by replacing the Sn atom in situ. It is found that additions of Ti, Al, and Cu atoms can increase the Wad, and Ag atom has the opposite effect. From the results of heat of segregation, doping Ti and Al into the interface is stable in thermodynamics and doping Cu and Ag is not stable. The forming of strong ionic‐covalent Ti‐O and Al‐O bonding contributes to the increase of the interfacial adhesion strength. The calculation results indicate that Ti and Al can act as active elements in Sn to solder ZrO2. The Ti‐O and Al‐O compounds formed at interface can improve the wetting and bonding between Sn‐based solder and ZrO2 ceramics. [ABSTRACT FROM AUTHOR]

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Diels‐Alder cycloaddition reaction is useful for generation of covalent derivatives of fullerenes. Diels‐Alder reactions of C70 and dienes usually take place at the carbon‐carbon bond that has a short bond length in C70, while the bonds with long lengths are generally unreactive. In this paper, we investigated the reactivities of Li+@C70 and Li@C70 toward Diels‐Alder reactions with cyclohexadiene by means of density functional theory calculations. We found that the thermodynamic and kinetic reactivities of the fullerene cage are changed significantly after the encapsulation of the lithium ion or atom. The encapsulated lithium ion causes a remarkable decrease of the activation barrier for the cycloaddition reaction, which can be ascribed to the enhanced orbital interaction between cyclohexadiene and the fullerene cage. The unreactive bond with a long length in C70 is activated efficiently after the encapsulation of the lithium atom. According to the activation‐strain model analysis, the improved reactivity of the long bond is associated with the small deformation energy and large interaction energy of the reactants. Unlike conventional Diels‐Alder reactions that proceed through concerted mechanism, the reaction of Li@C70 and cyclohexadiene undergoes an unusual stepwise mechanism because of the open‐shell electronic structure of Li@C70. [ABSTRACT FROM AUTHOR]

In this first of a series of publications, the X‐ray scattering factors for neutral atoms are revisited. Using the recently developed DBSR_HF program [Zatsarinny & Froese Fischer (2016). Comput. Phys. Comm.202, 287–303] the fully relativistic Dirac–Hartree–Fock ground‐state wavefunctions for all atoms with Z = 2–118 (He–Og) have been calculated using the extended average level scheme and including both the Breit interaction correction to the electronic motion due to magnetic and retardation effects, and the Fermi distribution function for the description of the nuclear charge density. The comparison of our wavefunctions with those obtained in several previous studies in terms of the total and orbital (spinor) electronic energies, and a number of local and integrated total and orbital properties, confirmed the quality of the generated wavefunctions. The employed dense radial grid combined with the DBSR_HF's B‐spline representation of the relativistic one‐electron orbitals allowed for a precise integration of the X‐ray scattering factors using a newly developed Fortran program SF. Following the established procedure [Maslen et al. (2006). International Tables for Crystallography, Vol. C, Section 6.1.1, pp. 554–589], the resulting X‐ray scattering factors have been interpolated in the 0 ≤ sin θ/λ ≤ 2 Å−1 and 2 ≤ sin θ/λ ≤ 6 Å−1 ranges using the recommended analytical functions with both the four‐ (which is a current convention) and five‐term expansions. An exhaustive comparison of the newly generated X‐ray scattering factors with the International Union of Crystallography recommended values and those from a number of previous studies showed an overall good agreement and allowed identification of a number of typos and inconsistencies in the recommended quantities. A detailed analysis of the results suggests that the newly derived values may represent an excellent compromise among all the previous studies. The determined conventional interpolating functions for the two sin θ/λ intervals show, on average, the same accuracy as the recommended parametrizations. However, an extension of each expansion by only a single term provides a significant improvement in the accuracy of the interpolated values for an overwhelming majority of the atoms. As such, an updated set of the fully relativistic X‐ray scattering factors and the interpolating functions for neutral atoms with Z = 2–118 can be easily incorporated into the existing X‐ray diffraction software with only minor modifications. The outcomes of the undertaken research should be of interest to members of the crystallographic community who push the boundaries of the accuracy and precision of X‐ray diffraction studies. [ABSTRACT FROM AUTHOR]

This paper revisits the generalized pseudospectral (GPS) method on the calculation of various radial expectation values of atomic systems, especially on the spatially confined hydrogen atom and harmonic oscillator. As one of the collocation methods based on global functions, the powerfulness and robustness of the GPS method has been well established in solving the radial Schrödinger equation with high accuracy. However, in our recent work, it was found that the previous calculations based on the GPS method for the radial expectation values of confined systems show significant discrepancies with other theoretical methods. In this work we have tackled such a problem by tracing its source to the GPS method and found that the method itself may not be able to obtain the system wave function at the origin. Combined with an extrapolation method developed here, the GPS method can fully reproduce the radial quantities obtained by other theoretical methods, but with more flexibility, efficiency, and accuracy. We apply the GPS‐extrapolation method to investigate the relatievistic fine structure and hyperfine splitting of confined hydrogen atom in s‐wave states where the zero‐point wave function dominates. Good agreement with previous predictions is obtained for confined hydrogen in low‐lying states, and benchmark results are obtained for high‐lying excited states. The perturbation treatment of the fine and hyperfine interactions is validated in the confining environment. [ABSTRACT FROM AUTHOR]

Muffin-tin potentials are the standard tool for calculating the potential surface of a cluster of atoms for use in the analysis of extended X-ray absorption fine-structure (EXAFS) data. The set of Cartesian coordinates used to define the positions of atoms in the cluster and to calculate the muffin-tin potentials is commonly also used to enumerate the scattering paths used in the EXAFS data analysis. In this paper, it is shown that these muffin-tin potentials are sufficiently robust to be used to examine quantitatively contributions to the EXAFS data from scattering geometries not represented in the original cluster. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) are widely regarded as promising next‐generation batteries due to their high theoretical specific capacity and low material cost. However, the practical applications of LSBs are limited by the shuttle effect of lithium polysulfides (LiPSs), electronic insulation of charge and discharge products, and slow LiPSs conversion reaction kinetics. Accordingly, the introduction of catalysts into LSBs is one of the effective strategy to solve the issues of the sluggished LiPS conversion. Because of their nearly 100% atom utilization and high electrocatalytic activity, single‐atom catalysts (SACs) have been widely used as reaction mediators for LSBs' reactions. Excitingly, the SACs with asymmetric coordination structures have exhibited intriguing electronic structures and superior catalytic activities when compared to the traditional M–N4 active sites. In this review, we systematically describe the recent advancements in the installation of asymmetrically coordinated single‐atom structure as reactions catalysts in LSBs, including asymmetrically nitrogen coordinated SACs, heteroatom coordinated SACs, support effective asymmetrically coordinated SACs, and bimetallic coordinated SACs. Particularly noteworthy is the discussion of the catalytic conversion mechanism of LiPSs spanning asymmetrically coordinated SACs. Finally, a perspective on the future developments of asymmetrically coordinated SACs in LSB applications is provided. [ABSTRACT FROM AUTHOR]

Single atomic catalysts have shown great potential in efficiently electro‐converting O2 to H2O2 with high selectivity. However, the impact of coordination environment and introduction of extra metallic aggregates on catalytic performance still remains unclear. Herein, first a series of carbon‐based catalysts with embedded coupling Ni single atomic sites and corresponding metallic nanoparticles at adjacent geometry is synthesized. Careful performance evaluation reveals NiSA/NiNP‐NSCNT catalyst with precisely controlled active centers of synergetic adjacent Ni‐N4S single sites and crystalline Ni nanoparticles exhibits a high H2O2 selectivity over 92.7% within a wide potential range (maximum selectivity can reach 98.4%). Theoretical studies uncover that spatially coupling single atomic NiN4S sites with metallic Ni aggregates in close proximity can optimize the adsorption behavior of key intermediates *OOH to achieve a nearly ideal binding strength, which thus affording a kinetically favorable pathway for H2O2 production. This strategy of manipulating the interaction between single atoms and metallic aggregates offers a promising direction to design new high‐performance catalysts for practical H2O2 electrosynthesis. [ABSTRACT FROM AUTHOR]

The crystal structures of bis[1-ethyl-6-fluoro-4-oxo-7-(piperazin-1-ium-4-yl)-1,4- dihydroquinoline-3-carboxylato]copper(II) sulfate heptahydrate, [Cu(C16H18FN3O3) 2]SO4.7H2O or [Cu(nor)2]SO4.7H2O (nor is norfloxacin), and bis{1-[2- (ethylsulfonyl)ethyl]-2-methyl-5-nitroimide}dinitratocopper(II), [Cu(NO3)2- (C8H13N3O4S)2] or [Cu(NO3)2(tnz)2] (tnz is tinidazole), were solved by X-ray diffraction. Both complexes crystallize in the space group P21/c, with Z = 4 (for nor) and Z = 2 (for ntz) molecules per unit cell. In [Cu(nor)2]SO4.7H2O, the CuII ion is at the centre of a square-planar environment, trans coordinated to two independent norfloxacin molecules in the zwitterionic form acting as bidentate ligands through one of the carboxyl (cbx) and the carbonyl (cb) O atoms. The solid is further stabilized by an extensive network of N--H. . .O(sulfate), N--H. . .O(cbx), N--H. . .OW, OW--H. . .O(sulfate) and OW--H. . .OW hydrogen bonds. The [Cu(NO3)2(tnz)2] complex is centrosymmetric, with the CuII ion in a square planar environment, coordinated to a tinidazole molecule acting as a monodentate ligand through its imidazole N atom and to one nitrate O atom. The vibrational FT-IR absorption spectra and thermal behaviour of the complexes were also studied and are briefly discussed based on the crystal structures. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we study the maximal function and local means characterizations and the non‐smooth atomic decomposition of the Triebel–Lizorkin type spaces with variable exponents F p ( · ) , q ( · ) s ( · ) , ϕ ( R n ). These spaces were recently introduced by Yang et al. and cover the Triebel–Lizorkin spaces with variable exponents F p ( · ) , q ( · ) s ( · ) ( R n ) as well as the classical Triebel–Lizorkin spaces F p , q s ( R n ), even the case when p = ∞. Moreover, covered by this scale are also the Triebel–Lizorkin‐type spaces F p , q s , τ ( R n ) with constant exponents which, in turn cover the Triebel–Lizorkin–Morrey spaces. As an application we obtain a pointwise multiplier assertion for those spaces. [ABSTRACT FROM AUTHOR]

This work extends previous efforts to model diffuse scattering from PZN (PbZn1/3Nb2/3O3). Earlier work [Welberry et al. (2005). J. Appl. Cryst. 38, 639-647; Welberry et al. (2006). Phys. Rev. B, 74, 224108] is highly prescriptive, using Monte Carlo simulation with very artificial potentials to induce short-range-order structures which were deduced as necessary from inspection of the data. While this gives valid results for the nature of the local structure, it does not strongly relate these structures to underlying crystal chemistry. In that work, the idea of the bond-valence sum was used as a guide to the expected behaviour of the atoms. This paper extends the use of the bond-valence sum from a qualitative guide to becoming a key aspect of the potential experienced by the atoms, through the idea of the global instability index, whose square has been shown to be proportional to the density functional theory energy of some systems when close to the minimum energy configuration. [ABSTRACT FROM AUTHOR]

This paper explores the radial projection method for locally finite planar point sets and provides numerical examples for different types of order. The main question is whether the method is suitable to analyse order in a quantitative way. The findings indicate that the answer is affirmative. In this context, local visibility conditions are also studied for certain types of aperiodic point sets. [ABSTRACT FROM AUTHOR]

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This document is a correction to a previous article titled "Superionic State in Alumina Produced by Nonthermal Melting." The correction addresses a mistake in a script that resulted in incorrect absorbed doses calculated for different electronic temperatures. The corrected values are provided in Table 1. The authors state that all other results and conclusions of the original paper are unaffected. The document includes contact information for the authors and the DOI for the original article. [Extracted from the article]

Aluminyl anions are low‐valent, anionic, and carbenoid aluminum species commonly found stabilized with potassium cations from the reaction of Al‐halogen precursors and alkali compounds. These systems are very reactive toward the activation of σ‐bonds and in reactions with electrophiles. Various research groups have detected that the potassium atoms play a stabilization role via electrostatic and cation⋯π interactions with nearby (aromatic)‐carbocyclic rings from both the ligand and from the reaction with unsaturated substrates. Since stabilizing K⋯H bonds are witnessed in the activation of this class of molecules, we aim to unveil the role of these metals in the activation of the smaller and less polarizable H2 molecule, together with a comprehensive characterization of the reaction mechanism. In this work, the activation of H2 utilizing a NON‐xanthene‐Al dimer, [K{Al(NON)}]2 (D) and monomeric, [Al(NON)]− (M) complexes are studied using density functional theory and high‐level coupled‐cluster theory to reveal the potential role of K+ atoms during the activation of this gas. Furthermore, we aim to reveal whether D is more reactive than M (or vice versa), or if complicity between the two monomer units exits within the D complex toward the activation of H2. The results suggest that activation energies using the dimeric and monomeric complexes were found to be very close (around 33 kcal mol−1). However, a partition of activation energies unveiled that the nature of the energy barriers for the monomeric and dimeric complexes are inherently different. The former is dominated by a more substantial distortion of the reactants (and increased interaction energies between them). Interestingly, during the oxidative addition, the distortion of the Al complex is minimal, while H2 distorts the most, usually over 0.77 ΔEdist≠. Overall, it is found here that electrostatic and induction energies between the complexes and H2 are the main stabilizing components up to the respective transition states. The results suggest that the K+ atoms act as stabilizers of the dimeric structure, and their cooperative role on the reaction mechanism may be negligible, acting as mere spectators in the activation of H2. Cooperation between the two monomers in D is lacking, and therefore the subsequent activation of H2 is wholly disengaged. [ABSTRACT FROM AUTHOR]

Only few efficient methods for the preparation of polyazoles containing three or four nitrogen atoms in each azole cycle exist. We have developed a novel synthetic strategy that allows the sequential assembly of 1,2,3‐triazole, 1,2,4‐triazole, and tetrazole fragments into a new stable polyazole. Along the novel strategy, some known procedures have been optimized to achieve better conversion, selectivity, and, in general, overall efficiency. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a vital chemical for modern human society. It is conventionally produced by the energy‐ and emission‐intensive Haber–Bosch process. Alternatively, sustainable NH3 production from renewable electricity‐driven electrolyzers has emerged as a promising route. Particularly, NH3 synthesis from nitrate (NO3−), a common pollutant in water and soil, by the nitrate reduction reaction (NO3RR) has drawn wide attention. Among various catalysts demonstrated recently, copper (Cu)‐based catalysts have been recognized as attractive candidates due to their availability, good activity, high NH3 selectivity, and facile reaction kinetics. In this review, the recent progress of Cu‐based NO3RR catalysts from the reaction mechanistic fundamentals to various catalyst design strategies, aiming at providing an on‐time summary, is summarized, and perspectives that can guide the rational and on‐demand design of Cu‐ and other earth‐abundant metal‐based catalysts for selective NO3RR toward sustainable NH3 production are elucidated. [ABSTRACT FROM AUTHOR]

Nonconventional luminescent materials have been rising stars in organic luminophores due to their intrinsic characteristics, including water‐solubility, biocompatibility, and environmental friendliness and have shown potential applications in diverse fields. As an indispensable branch of nonconventional luminescent materials, polysiloxanes, which consist of electron‐rich auxochromic groups, have exhibited outstanding photophysical properties due to the unique silicon atoms. The flexible Si‐O bonds benefit the aggregation, and the empty 3d orbitals of Si atoms can generate coordination bonds including N → Si and O → Si, altering the electron delocalization of the material and improving the luminescent purity. Herein, we review the recent progress in luminescent polysiloxanes with different topologies and discuss the challenges and perspectives. With an emphasis on the driving force for the aggregation and the mechanism of tuned emissions, the role of Si atoms played in the nonconventional luminophores is highlighted. This review may provide new insights into the design of nonconventional luminescent materials and expand their further applications in sensing, biomedicine, lighting devices, etc. [ABSTRACT FROM AUTHOR]

Invited for this month′s cover is the group of Steven Tait at Indiana University. The image shows single metal atoms stabilized by small molecules on a titanium dioxide powder support that are active in catalyzing ethylene hydrogenation. The Full Paper itself is available at10.1002/cssc.202100208. [ABSTRACT FROM AUTHOR]

When calculating derivatives of structure factors, there is one particular term (the derivatives of the atomic form factors) that will always be zero in the case of tabulated spherical atomic form factors. What happens if the form factors are non‐spherical? The assumption that this particular term is very close to zero is generally made in non‐spherical refinements (for example, implementations of Hirshfeld atom refinement or transferable aspherical atom models), unless the form factors are refinable parameters (for example multipole modelling). To evaluate this general approximation for one specific method, a numerical differentiation was implemented within the NoSpherA2 framework to calculate the derivatives of the structure factors in a Hirshfeld atom refinement directly as accurately as possible, thus bypassing the approximation altogether. Comparing wR2 factors and atomic parameters, along with their uncertainties from the approximate and numerically differentiating refinements, it turns out that the impact of this approximation on the final crystallographic model is indeed negligible. [ABSTRACT FROM AUTHOR]

Platinum usually offers the most effective active center for hydrogen evolution reaction (HER), because of the optimal trade‐off between the adsorption and desorption of hydrogeN atoms (H*) on Pt atoms. Herein, we report an unusual result regarding the active center of a HER catalyst, which was synthesized by electrodepositing traces of Pt nanoparticles (NPs) into a porous nitrogen‐rich dodecahedron matrix derived from zeolitic imidazolate framework ZIF‐8. With an ultra‐low Pt loading of 2.76 μg cm−2, the N‐Pt‐bonded catalyst can produce a current density of 117 mA cm−2 for the HER in 1.0 m H2SO4 at an overpotential of 50 mV, whereas the commercial Pt/C (300 μg cm−2 Pt) can only reach 50 mA cm−2 under the same conditions. Cyclic voltammetry demonstrates that both the H* adsorption and the Pt oxidation are not allowed to occur on this catalyst, due to a full surface coverage of the trace Pt NPs by imidazole. The results from the specially designed experiments indicate that the imidazole N atoms may act as proton anchor‐sites for the HER due to their electron donor nature. Density functional theory calculations also support a catalytic HER mechanism centered at the Pt‐supported N active center, which needs a Gibbs free energy of H* absorption (ΔGH*) significantly smaller than the absolute value of ΔGH* on the Pt(111) surface. We hope that the results of this study will encourage the research on novel N‐centered catalysts for the HER. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a new effective medium ratio following miniaturized meta-atom structure designed, fabricated and measured for dual-band that has multiple circular concentric metal rings printed one inside the other. The each ring of meta-atom structure delivers a magnetic resonance at different frequencies. The number of concentric ring resonator has created same number of resonances. A different analysis has been performed to verify distinct resonance frequencies, effective medium ratio and electromagnetic transmission properties simply by altering the design parameters. Computer simulation technology (CST) electromagnetic simulator which is commercially available is utilized to investigate the design of the meta-atom. The dual-band response has been displayed of the meta-atom in conjunction with negative index material property over the certain span in the microwave regime. The proposed structure has become suitable for S- and C-band applications and has achieved efficient electrically small microwave structure. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1233-1240, 2017 [ABSTRACT FROM AUTHOR]

Modern materials science increasingly advances via a knowledge-based development rather than a trial-and-error procedure. Gathering large amounts of data and getting deep understanding of non-trivial relationships between synthesis of materials, their structure and properties is experimentally a tedious work. Here, theoretical modeling plays a vital role. In this review paper we briefly introduce modeling approaches employed in materials science, their principles and fields of application. We then focus on atomistic modeling methods, mostly quantum mechanical ones but also Monte Carlo and classical molecular dynamics, to demonstrate their practical use on selected examples. [ABSTRACT FROM AUTHOR]

Heteroleptic Sr complexes, [Sr(dmamp)(btsa)]2⋅DME (1), [Sr(dmamb)(btsa)]2⋅DME (2), [Sr(dmamp)(hfac)]3⋅DME (3), [Sr(dmamb)(hfac)]3⋅DME (4), [Sr(dmamp)(tmhd)]n (5), and Sr[(dmamb)(tmhd)]n (6) (dmampH=1‐(dimethylamino)‐2‐methylpropan‐2‐ol, dmambH=1‐(dimethylamino)‐2‐methylbutan‐2‐ol, DME=dimethoxyethane, hfacH=1,1,1,5,5,5‐hexafluoropentadione, tmhdH=2,2,6,6‐tetramethylheptane‐3,5‐dione, btsa=bis(trimethylsilyl)amide) were successfully prepared by two‐step substitution reactions using aminoalkoxy and β‐diketonate ligands. All complexes were characterized using various methods, including Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, elemental analysis, and thermogravimetric analysis. Single‐crystal X‐ray diffraction of crystals of 1 and 2 revealed dimeric structures with Sr metal centres connected by μ2‐O bonding of an alkoxy O atom, whereas 3 was a trimer consisting of two μ3‐O bridges and three μ2‐O bridges by the dmamp and hfac ligands, respectively. [ABSTRACT FROM AUTHOR]