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A recently introduced neural network-based trial wave function, in combination with the variational Monte Carlo method, is applied to clusters of helium atoms of several sizes. Energies of clusters ranging from 11 to 24 atoms and radial distribution functions are reported in excellent agreement with those of the droplet model obtained with diffusion Monte Carlo. The abilities of neural networks to recognize patterns and relationships from distinct input features are explored, including identifying radial symmetry without explicitly considering it in the network inputs. The relation between data representation and the learning process is investigated, showing that high-quality data representations are critical for the efficient use of neural networks. [ABSTRACT FROM AUTHOR]

In this work, the geometric and electronic parameters of pure and vanadium-substituted anions of Lindqvist polyoxometalates have been investigated using DFT calculations. Active sites of all anions are identified through results on local and global reactivity descriptors. The results indicate that bridging oxygen atoms in all clusters are the most active sites. Using this, the mechanism of the catalytic generation of the hydroxyl radical from water was studied for the di-substituted Lindqvist polyoxometalate [V2Mo4O19]4−. This study provides a detailed understanding of this important intermediate step in photo-oxidation reactions. The mechanistic route makes it possible to locate transition states and intermediates structures and demonstrates that the pre-association of the water molecule leads to an H abstraction with an energy barrier of 26.42 kcal/mol and OH radical and [HV2Mo4O19]4− as products in this step. [ABSTRACT FROM AUTHOR]

Based on extensive global minimum searches augmented with first-principles theory calculations, we predict herein the first boron-based perfect tetrahedral clusters Td B16P4 (2) and Td B16As4 (3) which, as aromatic non-metal analogs of the experimentally observed Td Au20 (2003, Science299, 864), all contain a truncated Td B16 (1) cage at the center effectively stabilized by four trivalent non-metal atoms (P, As) at the corners. Detailed natural bonding orbital (NBO) and adaptive natural density partitioning (AdNDP) bonding analyses indicate that the valences of all the trivalent component atoms in these tetrahedral clusters are fully satisfied, rendering spherical aromaticity and extra stability to the systems. The IR, Raman, and photoelectron spectra (PES) of the concerned species are theoretically simulated to facilitate their characterizations in future experiments. [ABSTRACT FROM AUTHOR]

Copper has been reclusive with regard to its plasmonic investigations among the founding plasmonic metals. With the advent of technology and the associated improvements in understanding of plasmonics, copper has been able to make a stand for itself among its peers and even outshine them in a few aspects such as dielectric loss, cost, and a more intricate and facile tuning of the near and far field intensities of the plasmon-enhanced distributions. This review is aimed at highlighting the different classes of plasmonic copper (PC), ranging from its pristine version to the array of composited and alloyed compositions. The focus is on an all-encompassing review of PC with regard to its shortcomings and merits, its exploration for plasmonic applications, and emerging phenomena discovered due to the plasmonic virtue. We aim to bring about a comprehensive treatise of the investigations on PC, where the major discussions are on the topics of a generic treatise on surface plasmons (both localized and propagating), pristine copper and its potential for different applications, the almost inescapable phenomenon of oxidation, and the associations that copper has been made to form in order to be exploited for multiple uses such as chalcogenides, silicides, alloys, and other metamaterial architectures. Specific outcomes of the changes to the near and far-field distributions of PC in various conditions such as oxidized/alloyed/composited and stabilized have been discussed, highlighting the changes to PC in lieu of these modifications. The concluding sections highlight some fascinating compositions including multi-elemental copper and its atomic clusters and cursorily studied compositions which are among the few materials that could offer untapped capabilities which will be made evident from brief glimpses of their plasmonic character. The outlook for plasmonic copper has never been more promising, ranging from the need for comprehensive investigations of emerging material compositions and configurations (of both pristine and composited copper) to the realm of commercialization. Copper has, thus, been projected to be a viable alternative to existing options including the poster children of plasmonics, namely, silver and gold. [ABSTRACT FROM AUTHOR]

A molecular dynamics-based model of semi-solid formation from liquid melt of the novel Al–15Mg2Si–4.5Si composite is reported in the present study. Growth kinetics of Mg2Si phase is studied here at the pre-nucleation stage i.e., prior to the emergence of a stable nucleus. Moreover, insight has been grabbed on semi-solid processing of the said composite at atomic level, wherein the dynamic evolution of the Mg–Si clusters has been studied during cooling/semi solid slurry generation as well as during isothermal holding stage. The effect of variation of cooling rate on the number of clusters, average size of clusters and density of clusters has been investigated. The average size of clusters decays exponentially with cooling rate, whereas the average atomic density of clusters decays following a power-law relation with cooling rate. The change of the thermodynamic parameters (enthalpy and potential energy) during the phase transformation from liquid to semi-solid state are determined here, which are then employed to determine the value of interfacial free energy of Mg2Si-melt interface in the Al–15Mg2Si–4.5Si composite, along with the parameters obtained from the dynamic evolution of Mg-Si clusters. The paper also reports the temporal evolution of solid content within the melt, corresponding to the Mg2Si phase, during slurry generation as well as during isothermal holding stage. [ABSTRACT FROM AUTHOR]

Different transition metal loaded metal–organic frameworks (MOFs) have been extensively studied. However, little literature has been written about alkali and alkali-earth metal-loaded MOFs. In this study, we take the DPyDFP linker used for the construction of MOFs as an example. The structures and electronic properties of alkali metals and alkaline earth metals loaded DPyDFP clusters have been investigated using density functional theory. The results indicate that the structural stability of alkali metals and alkaline earth metals loaded DPyDFP clusters is less than that of transition metals loaded DPyDFP clusters. The interior of the DPyDFP clusters has not enough space to locate a large alkali metal or alkaline earth metal atom except for Li, Be and Mg. It indicates that if the IAM and IIAM atoms are loaded on the linker to build a MOF framework, Li, Be and Mg are worth considering. The DPyDFP-IIAM clusters exhibit more structural stability and chemically stable than corresponding DPyDFP-IAM clusters. The HOMOs and LUMOs of the DPyDFP-IAM and DPyDFP-IIAM clusters mostly surround N and C atoms. The IAM-N and IIAM-N bonds exhibit certain covalent character. Due to the limited charge transfer between the IAM (or IIAM) atoms and the DPyDFP clusters, the IAM (or IIAM) atoms are not a good choice to design the novel linker to build a MOF framework. [ABSTRACT FROM AUTHOR]

Context: Hydrogen has emerged as a promising clean energy carrier, underscoring the imperative need to comprehend its adsorption mechanisms. This study delves into the magnetic and electronic properties of Co-Mo-P clusters, aiming to unveil their catalytic potential in hydrogen production. Employing density functional theory (DFT), we optimized cluster configurations and scrutinized their magnetic behaviors. Our investigation unveiled 16 stable configurations of the ConMoP (n = 1 ~ 5) cluster, predominantly in steric forms. The magnetic attributes were primarily ascribed to the d orbitals of Co metal atoms, with Co3MoP exhibiting exceptional magnetic characteristics. Analysis of density of state diagrams revealed the prevalence of spin-up α-electrons in d orbitals, while spin-down β-electrons attenuated overall magnetic properties. Localized orbital (LOL) analysis highlighted stable covalent bonds within the clusters, affirming their catalytic potential. Orbital delocalization index (ODI) analysis revealed diverse spatial distribution ranges for orbitals across different configurations, suggesting a progressive attenuation of off-domain properties with increasing cluster size. Furthermore, infrared spectroscopy unveiled distinct vibrational peaks in various configurations, indicative of unique infrared activities. These findings contribute to a nuanced theoretical understanding of Co-Mo-P clusters and pave the path for future research aimed at augmenting their catalytic efficiency in hydrogen production. This study underscores the viability of Co-Mo-P clusters as alternatives to conventional Pt catalysts, offering insights into the design of novel materials for sustainable energy applications. Further research is warranted to explore the behavior of the Co-Mo-P system under diverse reaction conditions, fostering advancements in materials and energy science. Methods: In this study, we harnessed the ConMoP (n = 1 ~ 5) cluster as a simulation platform for probing the local structure of the material. Our aim was to scrutinize the magnetism, electronic characteristics influenced by the varying metal atoms within these clusters. A systematic exploration involved incrementing the number of metal atoms and expanding the cluster size to elucidate the corresponding property variations. Density functional theory (DFT) calculations were pivotal to our methodology, employing the B3LYP hybrid functional implemented in the Gaussian 16 software package. The ConMoP (n = 1 ~ 5) cluster underwent optimization calculations and vibrational analysis at the def2-tzvp quantization level, yielding optimized configurations with diverse spin multiplet degrees. To comprehensively characterize and visually represent the stability, electronic features, and catalytic attributes of these configurations, we employed a suite of computational tools. Specifically, quantum chemistry software GaussView and wave function analysis software Multiwfn played integral roles. Through the integrated use of these computational tools, we acquired valuable insights into the magnetism, electronic characteristics of the ConMoP (n = 1 ~ 5) cluster, shedding light on their dependency on distinct metal atoms. [ABSTRACT FROM AUTHOR]

Metal individual atoms and few-atom clusters show extraordinary catalytic properties for a variety of organic reactions, however, their implementation in total synthesis of complex organic molecules is still to be determined. Here we show a 11-step linear synthesis of the natural product (±)-Licarin B, where individual Pd atoms (Pd1) catalyze the direct aerobic oxidation of an alcohol to the carboxylic acid (steps 1 and 6), Cu2-7 clusters catalyze carbon-oxygen cross couplings (steps 3 and 8), Pd3-4 clusters catalyze a Sonogashira coupling (step 4) and Pt3-5 clusters catalyze a Markovnikov hydrosylilation of alkynes (step 5), as key reactions during the synthetic route. In addition, the new synthesis of Licarin B showcases an unexpected selective alkene hydrogenation with metal-free NaBH4 and an acid-catalyzed intermolecular carbonyl-olefin metathesis as the last step, to forge a trans-alkene group. These results, together, open new avenues in the use of metal individual atoms and clusters in organic synthesis, and confirm their exceptional catalytic activity in late stages during complex synthetic programmes. Individual metal atoms and few-atom metal clusters have shown promising catalytic activities, however, their exploitation in the total synthesis of complex organic molecules remains underexplored. Here, the authors develop a total synthesis of the bioactive natural product (±)-Licarin B involving key steps catalyzed by soluble individual Pd atoms and Cu/Pd/Pt clusters, achieving an 11-step linear synthesis and overall yield of 13.1%. [ABSTRACT FROM AUTHOR]

Metal individual atoms and few-atom clusters show extraordinary catalytic properties for a variety of organic reactions, however, their implementation in total synthesis of complex organic molecules is still to be determined. Here we show a 11-step linear synthesis of the natural product (±)-Licarin B, where individual Pd atoms (Pd1) catalyze the direct aerobic oxidation of an alcohol to the carboxylic acid (steps 1 and 6), Cu2-7 clusters catalyze carbon-oxygen cross couplings (steps 3 and 8), Pd3-4 clusters catalyze a Sonogashira coupling (step 4) and Pt3-5 clusters catalyze a Markovnikov hydrosylilation of alkynes (step 5), as key reactions during the synthetic route. In addition, the new synthesis of Licarin B showcases an unexpected selective alkene hydrogenation with metal-free NaBH4 and an acid-catalyzed intermolecular carbonyl-olefin metathesis as the last step, to forge a trans-alkene group. These results, together, open new avenues in the use of metal individual atoms and clusters in organic synthesis, and confirm their exceptional catalytic activity in late stages during complex synthetic programmes. Individual metal atoms and few-atom metal clusters have shown promising catalytic activities, however, their exploitation in the total synthesis of complex organic molecules remains underexplored. Here, the authors develop a total synthesis of the bioactive natural product (±)-Licarin B involving key steps catalyzed by soluble individual Pd atoms and Cu/Pd/Pt clusters, achieving an 11-step linear synthesis and overall yield of 13.1%. [ABSTRACT FROM AUTHOR]

The structures of phosphorus clusters with the number of atoms from 17 to 220 and their stability are studied theoretically. To calculate total energies of clusters a model is used that allows the highly accurate reproduction of density functional theory results. Calculations show that the most energetically favorable clusters Pn with 17 ≤ n ≤ 90 are single-stranded structures. At 91 ≤ n ≤ 125 these systems compete with double strands of fibrous phosphorus, and at n ≥ 126 fibrous phosphorus clusters become more favorable. The application of local stability criteria makes it possible to reveal the most stable clusters that are most likely to occur in the experiment. [ABSTRACT FROM AUTHOR]

Context: Under the ReaxFF/lg force field, the multiscale shock technique (MSST) was employed to investigate the decomposition behavior of perfect, dislocated, and twinned octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) at a velocity of 11 km/s. This study aimed to analyze the changes in system temperature, bond formation and breaking, variations in the number of small molecules, and the number of clusters. The results indicated that the sensitivity of dislocated HMX was the lowest, while the sensitivity of twinned and perfect HMX was comparable. Comparing the formation and breaking of bonds in HMX during the shock process, it was found that the change in the number of bonds in dislocated HMX was similar to that in perfect HMX, whereas twinning accelerated the breaking of bonds. By analyzing the changes in small molecular fragments (CO, CO2, H, H2, H2O, N2, N2H, NH2, NO, NO2, and O) during the shock process of HMX, it was found that dislocation had a relatively minor effect on the small molecular fragments, while twinning promoted the generation of CO, H, NO, and O and accelerated the decomposition of NO. A comparison of the number, weight, and atomic ratio of clusters under perfect, dislocated, and twinned conditions revealed that under the influence of shock, the number of clusters initially increased sharply and then decreased slowly. Meanwhile, compared to the perfect and dislocated explosives, the number of clusters under the twinned structure was significantly fewer, indicating that the twinned structure could reduce cluster formation. The proportion of oxygen to carbon in the twinned HMX was lower than that in the perfect and dislocated explosives, possibly due to the higher content of small molecular fragment O in twinned HMX. Methods: Different structures of HMX crystals were constructed, including twinned defect structure (with a supercell containing 6458 atoms), dislocation defect structure (with a supercell containing 2352 atoms), and perfect structure (also with a supercell containing 2352 atoms). The modeling of defect crystal structures was carried out using the Atomsk software. For the twinned defect structure, we first constructed a mirror symmetric structure of the original configuration and then merged these two structures together. For the dislocation defect structure, we shifted a segment of the originally ordered perfect crystal structure by a certain distance using Atomsk. Before conducting the simulations, we performed geometric optimization of the models using the conjugate gradient (CG) algorithm and carried out 10 ps of NVT and NPT simulations to equilibrate the energy, temperature, and other parameters within the system. Finally, a 50-ps MSST impact simulation was performed using Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). [ABSTRACT FROM AUTHOR]

First-principles calculations have been performed on (HfO 2) p and Hf q Zr r O 2 (q + r) clusters using DFT and TDDFT. The effect of Zr-substitution on the structural, electronic, thermodynamic, and optical properties of (HfO 2) p clusters has been investigated using B3LYP and B3PW91 functionals with LANL2DZ basis set. The calculated properties depend upon geometry, type, and number of atoms present in the clusters. Zr-substitution in (HfO 2) p clusters leads to the reduced molecular mass of Hf q Zr r O 2 (q + r) clusters so that they can be used in making light weight semiconductor devices. Hf 3 Zr 2 O 10 is found to be the most reactive after Zr-substitution in (HfO 2) 5 because of the minimum value of HOMO-LUMO gap. Zr-substitution in (HfO 2) 5 increases the refractive index of Hf 3 Zr 2 O 10 , making it suitable for multi-layer antireflecting coatings. The dielectric constant of Hf 3 Zr 2 O 10 has increased after Zr-substitution finding applications in the MOSFET industry. The absorption spectra can be tuned over the ultraviolet and visible regions depending upon the Zr-substitution. [ABSTRACT FROM AUTHOR]

Understanding and predicting the properties of polymers is vital to developing tailored polymer molecules for desired applications. Classical force fields may fail to capture key properties, for example, the transport properties of certain polymer systems such as polyethylene glycol. As a solution, we present an alternative potential energy surface, a charge recursive neural network (QRNN) model trained on DFT calculations made on smaller atomic clusters that generalizes well to oligomers comprising larger atomic clusters or longer chains. We demonstrate the validity of the polymer QRNN workflow by modeling the oligomers of ethylene glycol. We apply two rounds of active learning (addition of new training clusters based on current model performance) and implement a novel model training approach that uses partial charges from a semi-empirical method. Our developed QRNN model for polymers produces stable molecular dynamics (MD) simulation trajectory and captures the dynamics of polymer chains as indicated by the striking agreement with experimental values. Our model allows working on much larger systems than allowed by DFT simulations, at the same time providing a more accurate force field than classical force fields which provides a promising avenue for large-scale molecular simulations of polymeric systems. [ABSTRACT FROM AUTHOR]

Theoretical calculations of the electron density (taking into account the spin) of a model 16-atom carbon cluster with a manganese atom in a micropore showed that it is energetically favorable for manganese atoms to localize inside the pore and form metal nanoclusters in the carbon micropore. The magnetic moment of an ensemble of atoms surrounding a micropore with one manganese atom in it turned out to be quite large. An experimental method was proposed for introducing manganese clusters into bulk samples of nanoporous carbon with different porous structures, and the effect of these adsorbates on the magnetic properties of the samples was studied. In parallel, X-ray diffraction studies of the samples were carried out. It has been shown that Mn clusters near the surface are rather rapidly oxidized in air, as a result of which peaks associated with oxides predominate in the X-ray diffraction patterns. However, small Mn clusters have also been found. Measurements of the dependence of the magnetization of the samples on the applied field at T = 295 K showed the presence of nonlinearity and hysteresis characteristic of superparamagnetism or ferromagnetism. [ABSTRACT FROM AUTHOR]

Doping W into Li can greatly enhance the activity of Li-ion battery. However, the structures and properties of W-doped Li clusters remain elusive. In this study, we combined the global-minimum optimization and the density-functional theory calculations to systematically explore the lowest-energy structures of WLin (n = 2–12) bimetallic clusters and found it evolves from a triangle structure to a polyhedron pyramid structure, and finally to an endohedral cluster with W atom inside. In particular, W@Li12 is identified as a superatom. The cluster exhibits an icosahedral structure with 18 valence electrons, which has a notable HOMO–LUMO gap of 1.56 eV. The ab initio molecular dynamics simulations confirm the thermal stability of this cluster. Furthermore, the infrared spectrum has two vibration peaks, corresponding to the bending vibration and stretching vibration of the tungsten–lithium bond, respectively. The UV–Vis spectrum has two absorption peaks at the excitation energy of 2–4 eV, revealing the characteristics of the orbital electron transition. This study paves the way for the study of Li–W alloy to understand its mechanism in Li-ion battery. [ABSTRACT FROM AUTHOR]

In this paper, we used CALYPSO program which is conjuncted with DFT to investigate Li doped small-sized neutral Bn clusters. From ground-state and low energy structures, the properties and geometric significance of Li-doped boron clusters are greatly affected. Except for LiB9, which adds a B atom on preceding LiB8 boron wheel, the ground-state clusters of LiBn are formed by replacing the terminal boron atom of the Bn+1 clusters in the same size with a Li atom or by adding a Li atom to the Bn clusters. The transition point from 2 to 3D configuration of LiBn clusters appears at n = 5. The stability of LiBn clusters was analyzed by calculating the average binding energy, Gibbs free energy, first-order differential energy, second-order differential energy, HOMO–LUMO gap (the energy gap between the highest occupied and lowest unoccupied molecular orbital) and charge transfer. The results show that the LiB11 cluster with excellent symmetry and planar structure is the relative most stable structure. Molecular orbital and chemical bonding analysis indicated that the main reason for the stability of the LiB11 cluster is mainly due to the strong s-p bonding of B–B. [ABSTRACT FROM AUTHOR]

This paper presents results of density functional calculations of the atomic structure and electronic spectrum of (n = 12–17) clusters with the use of three distinct functionals. We analyze how the choice of the functional influences cluster structure optimization results and compare calculated electronic spectra of the most stable cluster isomers with measured photoelectron spectra, which makes it possible to assess the adequacy of the calculation method and identify the structure of the clusters. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) studies are performed on the geometric structures, stability, electronic properties of the RhmPdn (m + n = 13) clusters. All the configurations are 13-atomic icosahedral structures, with an atom in the central site. Rh1Pd12 has Ih symmetry and relatively suitable stability and electronic properties among these clusters, with moderate stability and inter-atomic binding interaction as the representative system for the study of NO molecule adsorption and dissociation. NO molecule tends to be end-on adsorbed on Rh1Pd12 with its N atom connecting to metal atoms of the cluster, preferably at the hollow site to the top or bridge site. For the dissociation of NO as a key step in its reduction, the adsorption and dissociation of NO on Rh1Pd12 cluster are overall exothermic reactions from the energies of the free NO molecule and the cluster. Doping Rh in the pure cluster affects little on the adsorption energy and dissociation energy barrier but much on the relative energy (the energy reduction from the free NO molecule and cluster to the final state). [ABSTRACT FROM AUTHOR]

Using computer methods (ToposPro software package), a combinatorial topological analysis and modeling of the self-assembly of the following crystal structures are carried out: Y20Cu20Mg64-oC104 (a = 4.136 Å, b = 19.239 Å, c = 29.086 Å, V = 2314.45 Å3, Cmcm), Y20Cu20Mg52-oC92 (a = 4.097 Å, b = 19.279 Å, c = 25.790 Å, V = 2037.30 Å3, Cmcm), and Y3(NiAl3)Ge2-hP9 (a = b = 6.948 Å, c = 4.156 Å, V = 173.78 5 Å3, P-62m). For the Y20Cu20Mg64-oC104 crystal structure, 52 variants of the cluster representation of the 3D atomic network with the 3, 4, and 5 structural units are established. Four crystallographically independent structural units in the form of a tetrahedron are determined: tetrahedron K4 = 0@CuMg3, tetrahedron K4 = 0@YMg3, tetrahedron K4 = 0@YCuMg2, and a supratetrahedron K6 = 0@YCu2Mg3. A variant of self-assembly with the participation of hexamers from six linked structural units is considered (K4B+ K4C)(K4A+ K6)(K4B+ K4C). For the Y20Cu20Mg64-oC92 crystal structure, 27 variants of cluster representation of the 3D atomic mesh with 3, 4, and 5 structural units are established. Three crystallographically independent structural units in the form of a tetrahedron are determined: tetrahedron K4 = 0@YCuMg2, cluster K6 = 0@6(Y2Mg4) in the form of double tetrahedrons YMg3, and a nine-atom supratetrahedron K9 = Mg@Y2Cu2Mg4 consisting of two YMg2Cu and two YMg3 tetrahedrons. A variant of the self-assembly involving trimers of three structural units K4+ K6+ K9 is considered. For the Y3(NiAl3)Ge2-hP9 crystal structure, eight variants of decomposition of the 3D atomic mesh into cluster structures with the participation of two structural units are established. A variant of the self-assembly with the participation of packing generatrices of seven-atom clusters-precursors K7 = 0@Y3(NiAl3) with the participation of Ge atoms-spacers is considered. The symmetry and topological code of the self-assembly processes of 3D-structures is reconstructed from clusters-precursor in the following form: primary chain → layer → framework. [ABSTRACT FROM AUTHOR]

Context: To comprehend the microscopic property alterations within the ConMoS cluster (n=1–5), this study investigates its internal interactions, electronic characteristics, and orbital correlations employing density functional theory. Structural optimization and theoretical analysis of the cluster are conducted using the Gaussian09 software package, considering various spin multiplicities and employing the B3LYP/def2tzvp quantum chemical method as the computational standard. The outcomes reveal the optimization of the cluster, resulting in 21 stable configurations while continually acquiring energy from the external environment. Analysis of the interaction region indicator functions, the independent gradient model based on Hirshfeld partition, the localized orbital indicator functions, and the electron localization function reveals a trend toward chemical bonding interactions within the interatomic interaction regions. Moreover, the interatomic forces exhibit a high likelihood of engaging in covalent bonding interactions. Both Co and Mo atoms display greater electron delocalization, facilitating the exchange of electrons with the external environment. The paper discuss electron space range, hardness and softness, polarizability, dipole moment, Mulliken population analysis, density of states, HOMO-LUMO diagram, and UV-Vis spectra. Configuration 5a exhibits the broadest electron delocalization and the highest reactivity. It maintains structural stability in external conditions and displays the most polarized molecules. Metal atoms in this cluster exhibit superior mobility compared to non-metal atoms. We elucidate the electron density aggregation region within the cluster. Configuration 1a demonstrates the highest correlation with molar absorption coefficient for its peak. Analyzing the HOMO and LUMO orbital delocalization index and center-of-mass distances revealed that the front orbits of configuration 5a exhibited a broad distribution in space and the minimum center-of-mass distance. Methods: This study presents a theoretical investigation of Co-Mo-S clusters employing density functional theory (DFT). DFT is a prevalent method for exploring the electronic structure and characteristics of atoms, molecules, and solids. The paper examines cluster attributes encompassing interatomic interactions, electronic properties, and frontier orbitals. Gaussian09 software is employed for optimizing cluster structures, while the analysis is augmented using Multiwfn wave function analysis software. By harnessing these theoretical and computational tools, it aims to delve deeper into cluster properties, yielding valuable insights. [ABSTRACT FROM AUTHOR]

Context: Mercaptopurine is an effective anticancer medicine yet known with serious adverse reactions, thus requiring further attempts to enhance its biological targeting. Small gold clusters Aun (n = 2–10) were used as model reactants to simulate the surface of gold nanoparticles. The computed results show that the drug molecules tend to anchor on the gold clusters at the S atom with the associated binding energies varying from −50 to −34 kcal mol−1 (in vacuum) and from −42 to −28 kcal mol−1 (in aqueous solution). Furthermore, the adsorption of the drug onto the gold surface is considered as a reversible process, and the mechanism of drug releasing was found to be triggerable by internal factors, such as a pH change or the concentrated presence of thiol amino acids in cancerous protein structures. Method: Calculations based on density functional theory (DFT) were performed to probe the nature of interactions between the drug and gold nanoparticles. Structural features, thermodynamic parameters, bonding characteristics, and electronic properties of the resulting complexes were investigated at the PBE//cc-pVTZ/cc-pVDZ-PP level. [ABSTRACT FROM AUTHOR]

Using repeated bundle extrusion of a Cu/NbTi composite, we have obtained a high-strength heterophase alloy having superconducting properties. X-ray diffraction characterization has shown that the material we obtained has an unstressed, relaxed structure in the form of self-consistent, locally diffusion-alloyed atomic groups ranging widely in size, which can be divided into three groups: (1) microcrystalline long-range-ordered particles about 450 Å in size, showing up as Debye peaks with sharp tops; (2) mesoscopic clusters with a nanoscale atomic order, responsible for broad diffuse lines; and (3) small low-dimensional atomic groups with short-range order (10–50 Å), responsible for incoherent diffuse X-ray scattering (very broad diffuse halos). [ABSTRACT FROM AUTHOR]

We propose an efficient scheme for realizing the 1 → n orbital state quantum cloning by using Rydberg superatoms. We place an ultracold Rydberg atomic ensemble which contains n individual ladder type Rydberg atoms inside the blocking ball to form a superatom, the quantum information is encoded the effective energy levels of superatom. Combined with quantum Zeno dynamics and shortcuts to adiabaticity, the 1 → 3 orbital state quantum cloning process can be quickly completed. Moreover, we generalize the idea to the case of 1 → n . At last, the influence of decoherence factors on fidelity is considered. The numerical simulation results show that high fidelity can be obtained. [ABSTRACT FROM AUTHOR]

A crystallographic analysis of two structures, monoclinic Nа8[{Re4(PO)4}(CN)12]⋅18H2O⋅CH3OH (I) and orthorhombic [(C6H5)4P]4 [Ta6I12(CN6)] (II), in which clusters of heavy atoms are significantly rarefied in space, so that their mutual arrangement cannot be explained only in terms of chemical interaction, has been performed. In structure I the crystallographic planes with a high atomic density ("skeletal" planes) are located in the regions with dhkl = 10–5.5 Å and dhkl < 3 Å. The planes in which atomic groups [Re4(PO)4] (playing the role of unified bulk objects) are concentrated are in fact selected in the first region. In the second region, ordering is implemented at the level of individual atoms. A crystallographic analysis showed that the structure basis is determined by the sites of heavy Re cations. A striking fact is that there are 1152 subcells and only 32 Re atoms per unit cell in this structure; i.e., only the fraction of 1/144 provides the basis of structure stability. In structure II "skeletal" planes are also absent in the range of dhkl from ∼7 to ∼4 Å. The planes in the range of large dhkl characterize cluster ordering, whereas the planes in the range of small dhkl characterize ordering of separate atoms. The geometry and local symmetry of the cluster group (Та6 octahedron) dictates the basis of translational symmetry—unified sublattice of sites, most of which are free of these atoms. The considered structures demonstrate the key role of heavy atoms in the formation of translational symmetry—the fundamental difference of the crystalline state from other condensed states. The newly formed structure retains partially local symmetry of cores (templates) of atomic groups, bound by strong chemical interactions, including the interactions between heavy and light atoms. The process of formation of a crystal structure from randomly oriented and randomly located templates—coherence assembly—is implemented according to the laws of dynamics of elastic media, where masses of atoms rather than their chemical characteristics are important. [ABSTRACT FROM AUTHOR]

The adsorption and dissociation of hydrogen molecule on small PdnAgm (n + m ≤ 4) clusters is studied employing density functional theory (DFT) calculations. The lowest energy structures of the PdnAgm clusters are initially presented. Based on the obtained structures, various geometries of H2 adsorption and dissociation with these clusters are examined. The cluster size and composition of the PdnAgm clusters are found to control the nature of the adsorption process. The results suggest that molecular adsorption is more favorable on the Pd atom and mixed clusters, while hydrogen dissociation is more favorable on the Pdn (n = 2–4) clusters. The Pd dimer and trimer are found to be the most reactive clusters for hydrogen adsorption, while single Ag atom is the least reactive one. The natural bond orbital (NBO) population analysis indicates that hydrogen atoms tend to draw electrons from the metal clusters in the dissociative form and donate electrons to the metal clusters in the molecular adsorption form. The density of states (DOS) of the PdnAgm trimers are also presented and discussed. The interaction and stabilities of cluster on the graphene support has also been performed. [ABSTRACT FROM AUTHOR]

In the process of searching for the plasmonic modes, various responses of the system for external fields are used to observe plasmons. However, these methods exist an obvious shortage. This is that some plasmonic modes may not have been found due they are not excited by the external fields. Recently, in two-dimensional square atomic clusters, we have presented the eigenequations of plasmon to study plasmons, and find that all the plasmon modes obtained by the resonant methods are predicted by the eigen-equation method. This effectively shows that the eigen-equation method is feasible and reliable in the process of finding plasmon modes. In this work, we generalize the eigen-equation method to the three-dimensional nanocubes. The effectiveness of the eigen method is further demonstrated, and various kinds of plasmons are displayed by charge distributions. The existence of the edge plasmons and the corner plasmons in nanocubes are further confirmed. [ABSTRACT FROM AUTHOR]

Context: The investigation of the stability, electronic properties, and catalytic activity of clusters ConMoP holds significant applications and implications in catalyst design, materials science, energy conversion and storage, and environmental protection. The study aims to delve into the unique features of the clusters ConMoP(n = 1 ~ 5), aiming to drive advancements in these related fields. The results obtained from the analysis revealed the stable configurations of the ten clusters, primarily characterized by steric structures. Furthermore, the energy of the clusters was found to increase continuously during growth, as indicated by calculations of atomic fragmentation energy and atomic binding energy. The researchers conducted an analysis of the Natural Population Analysis(NPA) charge, which revealed that Co atoms acted as electron donors, while P and Mo atoms acted as electron acceptors within the clusters. Additionally, an examination of the electrostatic potential indicated that Co and Mo atoms displayed nucleophilic tendencies, while P atoms exhibited electrophilic characteristics. Moreover, the density of states curves, HOMO and LUMO orbitals, and Kooperman's theorem were applied to the clusters ConMoP(n = 1 ~ 5).Through this study, a deeper understanding of the properties and behavior of clusters ConMoP has been achieved, shedding light on their potential as catalysts. The findings contribute to the existing knowledge of these clusters and provide a basis for further research and exploration in this field. Methods: In this study, we employed the clusters ConMoP(n = 1 ~ 5) to simulate the local structure of the material, enabling us to investigate the stability, electronic properties, and catalytic properties influenced by the metal atoms. By systematically increasing the number of metal atoms and expanding the cluster size, we explored the variations in these properties. Density functional theory (DFT) calculations were performed using the B3LYP hybrid functional implemented in the Gaussian09 software package. The clusters ConMoP(n = 1 ~ 5) underwent optimization calculations and vibrational analysis at the def2-tzvp quantization level, resulting in optimized configurations with different spin multiplet degrees. For data characterization and graphical representation of the stability, electronic properties, and catalytic properties of the optimized configurations, we utilized a range of computational tools. Specifically, the quantum chemistry software GaussView, wave function analysis software Multiwfn were employed. Through the comprehensive utilization of these computational tools, we gained valuable insights into the stability, electronic properties, and catalytic properties of the clusters ConMoP(n = 1 ~ 5) and their dependence on different metal atoms. [ABSTRACT FROM AUTHOR]

Context: In this study, theoretical and experimental analysis of the electrical, optical, and structural properties of a wurtzite-like zinc oxide (ZnO) nanostructure has been done. To investigate how quantum confinement affects the optical characteristics, two distinct ZnO clusters in nanowire structures have been investigated. The [(ZnO)55(H2O)4] system's HOMO–LUMO band gap (BG) was calculated to be 2.99 eV, which is quite close to the experimental measurement. It was found that the BG decreases with the increase in the number of atoms in the cluster in connection with the quantum confinement in nanoclusters. In addition, the lowest excitation energy in TD-DFT calculations of the identical system is in fairly good agreement with the experimental value with a difference of 0.1 eV. We conclude that the CAM-B3LYP functional has highly successful in reproducing the experimental data reported in the present study and previously reported experimental data. Methods: The geometrical optimization of two different sizes of ZnO clusters ([(ZnO)25(H2O)4] and [ZnO)55(H2O)4]) was performed using the CAM-B3LYP functional with no symmetry constraints applied in the gas phase. LANL2DZ basis sets were used for the Zinc (Zn) atom and 6-31G* basis sets for the O and H atoms. To determine their optical and electronic properties, excited state calculations of the pre-optimized structures were performed using the Time-Dependent DFT (TD-DFT) method. Multiwfn, Gaussum 3.0, and GaussView 5.0 programs were used to visualize the results. [ABSTRACT FROM AUTHOR]

This work presents a study on the surface tension of liquid Aluminum–Nickel (Al–Ni) alloys. Obtaining adequate values of surface tension for this system is not a simple task as these alloys present the formation of atomic clusters with short-range order at certain compositions, which dramatically influences surface tension. The Compound Forming Model predicts the influence of these clusters on surface tension, but experimental limitations have obstructed its validation due to deficient thermodynamic data. This work attempts to overcome some of these limitations by using Molecular Dynamics (MD). By comparing the obtained results from MD simulations with those of an equivalent system without clusters, it was possible to infer the role of the atomic clusters on Al–Ni surface tension. It was found that these clusters increase surface tension by decreasing the Al content at the surface. They achieve this reduction in Al content at the surface by trapping Al atoms and hindering their travel to the surface. [ABSTRACT FROM AUTHOR]

In this study, the amorphous-crystalline structural phase transformations that occur as a result of uniaxial compression strain applied to the Al amorphous model system obtained by rapid cooling from the liquid phase at 100 K and 300 K temperature values were tried to be investigated by molecular dynamics (MD) simulation method. The forces acting on Al atoms were determined from the gradient of the Embedded Atom Method (EAM) potential function, which includes many-body interactions. The formation of bcc and hcp interphases was observed during the transformation from the amorphous phase to the fcc crystalline phase at a strain rate value of 1 × 109 s−1. The evolution of atomic clusters with short-range order during the amorphous-crystal transformation was determined by radial distribution function (RDF), common neighbor analysis (CNA) and voronoi-polyhedra (VP) analysis, and the development of dislocations formed in the structure during the transformation was determined using DXA analysis. Amorphous-fcc-bcc–fcc and amorphous-bcc–fcc solid–solid phase transformations were determined for the model system at 300 K temperature and amorphous-fcc-bcc–fcc was determined by the applied compression strain. It was determined that the percentage of fcc unit cell structures was higher at 100 K temperature than 300 K temperature value. [ABSTRACT FROM AUTHOR]

The nano cutting process of Zr-based amorphous alloy was simulated by molecular dynamics simulation in this paper. Through the research on the changing rule of cutting force in nano cutting of Zr-based amorphous alloy, it is found that the cutting force increases continuously, and the cutting rate is large at the initial stage of nano cutting, which may be related to the shear deformation of the atomic clusters or atomic clusters in the shear transition zone. The effect of cutting tool rake angle on nano cutting process for Zr-based amorphous alloy was studied. The simulation results show that the cutting force decreases with the increase of the rake angle of the cutting tool, and the friction coefficient between the rake face and the chip also decreases slightly. With the increase of the rake angle of the cutting tool, the pushing effect of the tool on the Zr-based amorphous alloy chip and the overall bending of the chip are weakened, leading to the increase of the chip height. The number of high-temperature atoms in the Zr-based amorphous alloy workpiece also decreases with the increase of the tool rake angle, and the cutting temperature distribution on the workpiece diffuses to the interior of the workpiece with the tool fillet as the center. [ABSTRACT FROM AUTHOR]

A novel surface engineering technology involving a powder-fed friction stir process (APF-FSP) is suggested for fabricating an Al5086 – GRN – ηSiC hybrid surface composite. The structure of the composite is studied by scanning and transmission electron microscopy. The ultimate compressive strength, the HV hardness and the modulus of elasticity of the composite are determined. It is shown that the structure of the composite is represented by aluminum matrix grains up to about 8 μm in size and uniformly distributed graphene/nano-SiC (GRN/nano-SiC) reinforcements. The graphene forms multilayer atomic clusters in the aluminum matrix due to mechanical exfoliation of the graphite. The composite obtained has high hardness (145 HV0.3) and ultimate compressive strength (385 ± 5 MPa). [ABSTRACT FROM AUTHOR]

The article considers the results of studies of the emission spectra of CHF3, CCl2F2, SF6 upon excitation by pulsed laser radiation. We used Nd : YAG laser, λ = 1064 nm, τ = 5 ns, and Epulse = 0.8 J. The spectral range of 3–20 nm was studied. We used capillary and supersonic conical nozzles with dcrit = 145 μm, 2α = 12°, L = 5 mm, and dcrit = 450 μm, 2α = 11°, L = 5 mm to form an atomic cluster beam. The emission spectra for various gas targets were obtained, the obtained spectra were deciphered, and the ions emitting in this spectral range were determined. We observed that with increasing particle concentration in the zone of laser spark, the radiation intensity increases. In this case, the intensity of ion lines with high degrees of ionization increases faster. [ABSTRACT FROM AUTHOR]

In this work, we would like to explore the possibility of studying phase change behaviour in pure Lennard-Jones clusters as well as the effect of introducing a heteroatom. The system studied are Ar 10 , Xe 10 and Ar 10 - 1 Xe 1 as well as Ar 10 - 9 Xe 9 . The phase change is followed by the temperature variation in classical configuration heat capacity. As the heat capacity is calculated by evaluating the variance in the energy of the isomers possible, an important aspect is to sample the Lennard-Jones surface effectively and pick out as many isomers which are possible for this system. The sampling at various temperatures has been done using the replica exchange Monte Carlo or Parallel tempering procedure. The main focus of the present work is to see how the phase change behaviour is affected on going from the pure Lennard-Jones systems to the once possessing dopants. To further aid in the understanding bond length fluctuation parameter has also been calculated for all the systems with changing temperature along with the classical configuration. Synopsis: The phase change behavior of pure Lennard-Jones clusters and the effect of introducing a heteroatom was studied using replica exchange Monte Carlo or parallel tempering techniques and examining the classical configuration heat capacity and bond length fluctuation parameter. The systems studied were Ar10 , Xe10 and Ar10−1 Xe1 as well as Ar10−9 Xe9. [ABSTRACT FROM AUTHOR]

In this work, the potential of monohydrate Lithium hydroxide (LiOH) as a high capacity adsorbent for CO2 capture was investigated experimentally and theoretically. The effects of operating parameters, including temperature, pressure, LiOH particle size and LiOH loading, on the CO2 capture in a fixed-bed reactor have been experimentally explored using response surface methodology (RSM) based on central composite design. The optimum conditions obtained by the RSM for temperature, pressure, mesh and maximum adsorption capacity were calculated as 333 K, 4.72 bar, 200 micron and 559.39 mg/g, respectively. The experiments were evaluated using isotherm, kinetic and thermodynamic modeling. Isotherm modeling showed that Hill model could deliver a perfect fit to the experimental data, based on the closeness of the R2-value to unity. The kinetics models showed that the process was chemical adsorption and obeyed the second order model. In addition, thermodynamic analysis results showed that the CO2 adsorption was spontaneous and exothermic in nature. In addition, based on the density functional theory, we investigated the chemical stability of LiOH atomic clusters and examined the effects of LiOH nanonization on the physical attraction of carbon dioxide. [ABSTRACT FROM AUTHOR]

Exploration of the structure formation and dynamics of animate and inanimate matter on the nanometer scale is a highly interdisciplinary field of rapidly emerging research. It is relevant for various molecular and nanoscale systems of different origins and compositions and concerns numerous phenomena originating from physics, chemistry, biology, and materials science. This topical issue presents a collection of research papers devoted to different aspects of the Dynamics of Systems on the Nanoscale. Some of the contributions discuss specific applications of the research results in several modern and emerging technologies, such as controlled nanofabrication with charged particle beams or the design and practical realization of novel gamma-ray crystal-based light sources. Most works presented in this Topical Issue were reported at the joint Sixth International Conference "Dynamics of Systems on the Nanoscale" and the tenth International Symposium "Atomic Cluster Collisions" (DySoN–ISACC 2021), which were held in Santa Margherita Ligure, Italy, in October 2021. [ABSTRACT FROM AUTHOR]

In this work, we report evolution of atomic clusters in a highly under-expanded supersonic jet of Argon. A high resolution and sensitive Rayleigh scattering based experimental set-up is designed to overcome the limitations encountered in conventional set-ups. Further, the measurement range could be extended from a few nozzle diameters to 50 nozzle diameters. Simultaneously, we had been able to generate 2D profiles of the distribution of clusters inside the jet. This paves the way to track the growth of clusters along the flow direction experimentally, which until now was limited to few nozzle diameters. The results show that spatial distribution of clusters inside the supersonic core deviates considerably from the prediction of the free expansion model. We exploit this to estimate cluster growth along the expansion direction. Further, it is observed that the growth of the clusters gets saturated after a certain distance from the nozzle. At the jet boundary, we see substantial cluster strengthening immediately upstream of barrel shock while the normal shock exhibits disintegration of clusters. These observations are noticed for the first time, which, we believe will further the understanding of cluster dynamics in a supersonic jet. [ABSTRACT FROM AUTHOR]

Size-selected iron oxide nanoclusters are outstanding candidates for technological-oriented applications due to their high efficiency-to-cost ratio. However, despite many theoretical studies, experimental works on their oxidation mechanism are still limited to gas-phase clusters. Herein we investigate the oxidation of graphene-supported size-selected Fen clusters by means of high-resolution X-ray Photoelectron Spectroscopy. We show a dependency of the core electron Fe 2p3/2 binding energy of metallic and oxidized clusters on the cluster size. Binding energies are also linked to chemical reactivity through the asymmetry parameter which is related to electron density of states at the Fermi energy. Upon oxidation, iron atoms in clusters reach the oxidation state Fe(II) and the absence of other oxidation states indicates a Fe-to-O ratio close to 1:1, in agreement with previous theoretical calculations and gas-phase experiments. Such knowledge can provide a basis for a better understanding of the behavior of iron oxide nanoclusters as supported catalysts. Iron oxide nanoclusters are of interest for a broad range of applications, but limited experimental information on their oxidation mechanism is available outside of the gas phase. Here, the oxidation of graphene-supported size-selected Fen clusters is studied using high-resolution X-ray Photoelectron Spectroscopy. [ABSTRACT FROM AUTHOR]

The scaling up of the intensity of beams of atomic clusters (nanoparticle beams) creates a new route to the fabrication of functional nanostructured materials. A challenge is to present, to the directed beam, high surface areas of the desired support material, for decoration by the clusters at local sub-monolayer densities. Then, the clusters and their properties can be preserved. Here we employ the Matrix Assembly Cluster Source (MACS) to demonstrate and characterise the deposition of lead clusters, with size of order 2 nm, into planar sheets of porous carbon paper, a material employed in electrode fabrication. We find that clusters are deposited to a depth comparable with the pore size of the carbon, ~ 50 μm, giving rise to a metal loading of ~ 0.05 mg cm−2 of carbon paper. The functionality of the nanocomposite film so created is demonstrated by its use as an electrode for the electrochemical generation of oxidising species suitable for water purification. [ABSTRACT FROM AUTHOR]

Metal nanoclusters composed of noble elements such as gold (Au) or silver (Ag) are regarded as superatoms. In recent years, the understanding of the materials composed of superatoms, which are often called superatomic molecules, has gradually progressed for Au-based materials. However, there is still little information on Ag-based superatomic molecules. In the present study, we synthesise two di-superatomic molecules with Ag as the main constituent element and reveal the three essential conditions for the formation and isolation of a superatomic molecule comprising two Ag13−xMx structures (M = Ag or other metal; x = number of M) connected by vertex sharing. The effects of the central atom and the type of bridging halogen on the electronic structure of the resulting superatomic molecule are also clarified in detail. These findings are expected to provide clear design guidelines for the creation of superatomic molecules with various properties and functions. Icosahedron-based M13 nanoclusters are common building blocks to produce atomically precise superatomic molecules, but our understanding of the chemistry governing the connection between icosahedral M13 units is limited. Here, the key factors influencing the vertex sharing connection between Ag13−xMx structures are studied, and the effects of different central metal atoms and the type of bridging halogen atom are clarified. [ABSTRACT FROM AUTHOR]

This work presents a study on the surface tension of liquid Aluminum–Nickel (Al–Ni) alloys. Obtaining adequate values of surface tension for this system is not a simple task as these alloys present the formation of atomic clusters with short-range order at certain compositions, which dramatically influences surface tension. The Compound Forming Model predicts the influence of these clusters on surface tension, but experimental limitations have obstructed its validation due to deficient thermodynamic data. This work attempts to overcome some of these limitations by using Molecular Dynamics (MD). By comparing the obtained results from MD simulations with those of an equivalent system without clusters, it was possible to infer the role of the atomic clusters on Al–Ni surface tension. It was found that these clusters increase surface tension by decreasing the Al content at the surface. They achieve this reduction in Al content at the surface by trapping Al atoms and hindering their travel to the surface. [ABSTRACT FROM AUTHOR]

Interatomic Coulombic Decay (ICD) and related interatomic and intermolecular autoionization mechanisms are ubiquitous decay processes of excited atoms and molecules in an environment. It is commonly accepted that the efficiency of ICD of an ionized atom in a cluster increases with an increasing number of nearest neighbors. Here, we present a method for experimental validation of this assumption by a site-specific and quantitative comparison of ICD and its main competitor, Auger decay, in core-level ionized Kr clusters. Our results are in quantitative agreement with scaled theoretical calculations on Kr2. Energy and charge transfer processes like Interatomic Coulombic Decay (ICD) play an important role in the relaxation of excited atoms or molecules in dense media such as biological tissue. Here, we present a method to experimentally determine the site-specific efficiency of the ICD process, which is in quantitative agreement with theoretical calculations. [ABSTRACT FROM AUTHOR]

Bond lengths and bond indices in As20, Ni12As20, [As@Ni12As20]3–, As@C60, and As@C70 clusters were calculated by the DFT PBE0/SDD method. The oxidation and reduction degrees of the endo-atom and the shell are expressed in terms of the populations of one-electron states localized in these components of the complexes. Each arsenic atom in clusters has an entirely localized lone electron pair. The arsenic atom inside fullerenes retains the electronic configuration and spin of the free arsenic atom ground state. Inside the [Ni12As20]6– shell, it has the oxidation state 3+. There is no covalent bond between the endo-atom and the shell in the clusters. The bond indices refute the opinion about the "onion" [As@Ni12@As20]3– structure: the nickel atoms are not bonded to each other and the As–As bond indices are three times lower than in As20. [ABSTRACT FROM AUTHOR]

Due to relativistic effects, Au exhibits unusual properties among the coinage metals. In addition to being reactive at the nanoscale, Au behaves like a hydrogen atom in small clusters. It was recently shown that in Au2Fn (n = 1, 2) clusters, one of the Au atoms behaves like a normal metal atom while the other behaves like a halogen. To see whether this behavior persists in clusters containing a larger number of Au and F atoms, we have carried out a comprehensive study of the equilibrium geometries and electronic structure of neutral and anionic Au2Fn (n = 1–11), Au3Fn (n = 1–4), and Au4Fn (n = 1–5) clusters as well as their corresponding electron affinities using density functional theory. As the number of F atoms exceeds the number of Au atoms, the Au–Au bonds become weak and in most cases break, while those that exist are between the Au and F atoms. Analogous to Au2Fn (n = 1, 2) clusters, the Au atoms in the above neutral clusters carry a positive charge, but their amount depends upon the relative composition of AumFn clusters; the Au atoms bonded to F carry a larger charge than that bonded to an Au atom. In clusters where no Au–Au bonds exist, the Au atom bonded to more F atoms carries a larger positive charge than those bonded to a lesser number of F atoms. In anionic clusters, the situation is different; when the number of F atoms is less than or equal to the Au atoms, the Au atom bonded to F carries a positive charge while the other(s) carry a negative charge, mimicking the chemistry of halogens. This Janus behavior of Au in terms of the charge they carry depends upon the relative abundance of Au and F and is attributed to the relativistic effects. Equally interesting, contrary to the conventional rule, the electron affinities of Au3Fn (n = 2–4) and Au4Fn (n = 1, 3) clusters are larger than that of Cl, making them superhalogens. [ABSTRACT FROM AUTHOR]

This paper presents results of computer simulation experiments based on density functional calculations of the atomic structure and electronic spectrum of (n = 15–17) clusters. Based on the Wade–Mingos rules, we identify general trends in the formation of monoanionic hafnium-doped Sn clusters, which make it possible to optimize prognostic studies concerned with a search for novel nanostructured materials. We compare calculation results obtained with the B3LYP, B3PW91, and PBE functionals in combination with the SDD basis set and analyze the effect of the functionals on atomic structure optimization results. An optimal strategy is proposed for computer simulation experiments dealing with modeling of the spatial structure of Sn-based clusters and confirmed by comparison with available experimental data. [ABSTRACT FROM AUTHOR]

On the basis of quantum-chemical analysis, it has been shown that the formation of silicon carbide nanoclusters can occur due to the chemical reaction between two CH3SiCl3 molecules on the first step of the process with the subsequent reaction between CH3SiCl3 and the formed clusters, rather than due to the homolytic C–Si bond rupture in the CH3SiCl3 molecule. Cases where a chlorine atom of a CH3SiCl3 molecule interacts with one hydrogen atom of another CH3SiCl3 molecule or cluster, and three chlorine atoms of a methyltrichlorosilane molecule form a three-center complex with three hydrogen atoms of a cluster have been considered. It is shown that the second case leads to the formation of SiC nanoparticles. [ABSTRACT FROM AUTHOR]

The electron transport through the Mo6S8 cluster located between two one-dimensional electrodes composed of aluminum atoms is studied by non-equilibrium Green's function method. It is shown that the electron transport depends on the interatomic distances between the terminal atoms of the electrode and cluster, as well as the cluster orientation relative to the electrodes. Conditions under which the maximum probability for the electron transport can be achieved are proposed. [ABSTRACT FROM AUTHOR]

This article mainly intended to investigate the structural and electronic properties of Pt13 cluster with two atoms doped M (Ag, Ir, and Pd) within the framework of the density functional theory. The plane wave and DoS methods along with spin-polarized exchange–correlation functionals have been used to study the isomers of Pt11M2-doped clusters mainly to categorize the lowest energy structures. This work is mainly to analyze the advantage/impact on two atoms doping over the single-atom doping. This work also discusses study on placing two doping atoms at adjacent and opposite positions. In addition to this, the atom clusters stability has been examined based on the total energy and binding energy calculations. The comparative analysis of Pt11M2 isomer reveals that adjacent doping positions show the lowest energy than opposite positions. Further study of Bader charge analysis of Pt11M2 cluster indicates charge transfer within the atomic structure ranging from − 1.37 to + 1.17e. Overall, this article outlines the significance of placing the atoms at strategic places of the adjacent site and opposite site of Pt11M2 cluster as well as in obtaining the lowest energy structure. [ABSTRACT FROM AUTHOR]

The structures, electronic and magnetic properties of the FexNy (x = 1–4, y = 1–4) molecules adsorbed graphene have been investigated by using first-principles. The results show that Fe atoms of the FexNy molecules prefer to approach the center of hexagonal ring of the C66H22 clusters and N atoms tend to form N2 structure. The FeNyC66H22 clusters are more structurally stable than corresponding FexNC66H22 clusters. FexNy molecules can improve the chemical activity of the C66H22 clusters. The C66H22 clusters can increase the chemical activity of the FexNy molecules except for the Fe2N and Fe4N molecules. The FexN fragments rather than the FeNy fragments lose more electrons to the C66H22 clusters. Spin densities of the FexNy fragments of the FexNyC66H22 clusters degenerate to zero. [ABSTRACT FROM AUTHOR]

Ion irradiation is a powerful tool to tune properties of semiconductors and, in particular, of gallium oxide (Ga2O3) which is a promising ultra-wide bandgap semiconductor exhibiting phase instability for high enough strain/disorder levels. In the present paper we observed an interesting interplay between the disorder and strain in monoclinic β-Ga2O3 single crystals by comparing atomic and cluster ion irradiations as well as atomic ions co-implants. The results obtained by a combination of the channeling technique, X-ray diffraction and theoretical calculations show that the disorder accumulation in β-Ga2O3 exhibits superlinear behavior as a function of the collision cascade density. Moreover, the level of strain in the implanted region can be engineered by changing the disorder conditions in the near surface layer. The results can be used for better understanding of the radiation effects in β-Ga2O3 and imply that disorder/strain interplay provides an additional degree of freedom to maintain desirable strain in Ga2O3, potentially applicable to modify the rate of the polymorphic transitions in this material. [ABSTRACT FROM AUTHOR]