Search

The structures and chemical bond evolution of ditantalum doped carbon clusters Ta2Cn−/0 (n = 1–7) were studied via size-selected anion photoelectron spectroscopy and theoretical calculations. It is found that Ta2C−/0 has a triangular structure and Ta2C2−/0 has a quasi-rhombus structure with C2v symmetry. Ta2C3− has a quasi-planar structure with a carbon atom and a C2 unit interacting with two tantalum atoms, and the lowest-energy isomer of neutral Ta2C3 has a triangular bipyramid structure with three carbon atoms around the Ta2 unit. Ta2C4−/0 has two C2 units connected with the Ta2 unit in parallel. Two isomers of Ta2C5− are observed, where both isomers have one carbon atom and two C2 units bound to the Ta2 unit in different ways. The most stable structure of neutral Ta2C5 has one carbon atom added on top of the Ta2C4 cluster. The most stable structures of Ta2C6-7−/0 can be viewed as a C2 unit and a C3 unit capping a butterfly like Ta2C4 structure, respectively. Molecular orbital analysis shows that neutral Ta2C3 has a large gap between its highest occupied molecular orbital and lowest unoccupied molecular orbital. Chemical bonding analysis reveals that the Ta–Ta interactions in Ta2Cn−/0 (n = 1–7) clusters are slightly weaker than the Ta–Ta interaction in bare Ta2 due to the participation in forming multicenter bonds. [ABSTRACT FROM AUTHOR]

The ring-opening reaction of aromatic molecules is a significant and critical process for the construction of carbon-based and related functional materials with desired structures and properties. However, direct observation and control of such a process at a molecular level remains a challenge. Here, we employed the octahedral voids in endohedral metallofullerene (EMF) crystals as nanoreactors to accommodate aromatic m-xylene molecules and regulate the ring-opening reaction of guest m-xylene by applying a high pressure. We found that the ring-opening reaction of m-xylenes strongly depends on the degree of charge transfer between m-xylene and EMF, which can be tuned by varying the electronegativity of the carbon cages with different endohedral metals. A positive relationship between the electronegativity of fullerenes and the reactivity of m-xylene was revealed. This work demonstrates the potential of tuning the ring-opening reaction of aromatic molecules by charge transfer and manipulates the reaction at a molecule level, providing new insights into the synthesis of carbon materials and fullerene derivatives. [ABSTRACT FROM AUTHOR]

Although widely studied experimentally in the 1990s, the structure and properties of low-dimensional or high-pressure phases of fullerenes have recently been re-examined. Remarkably, recent experiments have shown that transparent, nearly pure amorphous sp3-bonded carbon phases can be obtained by heating a C60 molecular crystal at a high pressure. With the additional aim of testing the ability of three classical carbon potentials reactive empirical bond order, environment-dependent interatomic potential, and reactive force-field to reproduce these results, we investigate the details of the structural transformations undergone by fullerene crystals over a wide range of pressures and temperatures. All the potentials tested show that the initial polymerization of fullerenes is accompanied by negative thermal expansion, albeit in slightly different ranges. However, more significant differences in structural and mechanical properties are observed in the amorphous phases, in particular the sp3 carbon fraction and the existence of layered amorphous carbon. Overall, these results indicate to which extent classical reactive potentials can be used to explore phase transitions over a wide range of pressures and temperatures. [ABSTRACT FROM AUTHOR]

As a newly synthesized two-dimensional (2D) carbon material, monolayer quasi-hexagonal phase fullerene (qHP C60) has an excellent electronic structure and low thermal conductivity. qHP C60 attracted significant attention from scientists because it has potential applications in thermoelectric materials. Thermoelectric properties of 2D materials significantly depend on the transport of carriers (such as electrons and phonons), and strain engineering is an essential method for modulating the transport of electrons and phonons in 2D materials. However, the strain engineering method for the modulation of the thermoelectric properties of monolayer qHP C60 has not been reported yet. In the present paper, the first-principles combined with the non-equilibrium Green's function method are used to investigate the ballistic transport properties of electrons and phonons in monolayer qHP C60. The effects of temperature, chemical potential, and biaxial tensile strain on the thermoelectric transport parameters (including conductivity, Seebeck coefficient, power factor, and thermal conductivity) as well as the figure of merit (ZT) of monolayer qHP C60 are presented, compared, discussed, and analyzed. We found that monolayer qHP C60 exhibits anisotropic characteristics in electron and phonon transport properties, showcasing outstanding thermoelectric properties. The distinctive quasi-hexagonal phase fullerene network structure offers a novel platform for exploring innovative 2D thermoelectric materials in research. This study provides crucial theoretical insights to guide the designing and implementation of 2D thermoelectric materials based on fullerenes. [ABSTRACT FROM AUTHOR]

Fullerene-assembled low-dimensional materials have been experimentally realized in polymorphic forms and have attracted significant interest very recently. Here, we predict a two-dimensional (2D) honeycomb lattice material TM2(C60)3 (TM = Cr, Mo, and W) assembled from exohedral metallofullerene clusters TM(C60)3 that could exhibit planar triangular geometries. According to first-principles calculations combined with Monte Carlo simulations, we suggest that these 2D assembled materials exhibit various exotic physical properties, including ferromagnetism, ferroelectricity, and quantum anomalous Hall effect. Interestingly, mechanical strains could effectively tune their magnetic moments and switch the conducting spin channel of the Dirac bands at the Fermi level. Our work provides a new cluster-assembly design strategy toward cluster-assembled 2D materials based on fullerene characters. [ABSTRACT FROM AUTHOR]

Ge-Sb-Te (GST) alloys are leading phase-change materials for data storage due to the fast phase transition between amorphous and crystalline states. Ongoing research aims at improving the stability of the amorphous phase to improve retention. This can be accomplished by the introduction of carbon as a dopant to Ge2Sb2Te5, which is known to alter the short- and mid-range structure of the amorphous phase and form covalently bonded C clusters, both of which hinder crystallization. The relative importance of these processes as a function of C concentration is not known. We used molecular dynamics simulation based on density functional theory to study how carbon doping affects the atomic structure of GST-C. Carbon doping results in an increase in tetrahedral coordination, especially of Ge atoms, and this is known to stabilize the amorphous phase. We observe an unexpected, non-monotonous trend in the number of tetrahedral bonded Ge with the amount of carbon doping. Our simulations show an increase in the number of tetrahedral bonded Ge up to 5 at.% C, after which the number saturates and begins to decrease above 14 at.% C. The carbon atoms aggregate into clusters, mostly in the form of chains and graphene flakes, leaving less carbon to disrupt the GST matrix at higher carbon concentrations. Different degrees of carbon clustering can explain divergent experimental results for recrystallization temperature for carbon doped GST. [ABSTRACT FROM AUTHOR]

We present a comprehensive analysis of the structure–property relationship in small molecule non-fullerene acceptors (NFAs) featuring an acceptor–donor–acceptor configuration employing state-of-the-art quantum chemical computational methods. Our focus lies in the strategic functionalization of halogen groups at the terminal positions of NFAs as an effective means to mitigate non-radiative voltage losses and augment photovoltaic and photophysical properties relevant to organic solar cells. Through photophysical studies, we observe a bathochromic shift in the visible region for all halogen-functionalized NFAs, except type-2, compared to the unmodified compound. Most of these functionalized compounds exhibit exciton binding energies below 0.3 eV and ΔLUMO less than 0.3 eV, indicating their potential as promising candidates for organic solar cells. Selected candidate structures undergo an analysis of charge transport properties using the semi-classical Marcus theory based on hopping transport formalism. Molecular dynamics simulations followed by charge transport simulations reveal an ambipolar nature of charge transport in the investigated NFAs, with equivalent hole and electron mobilities compared to the parent compound. Our findings underscore the crucial role of end-group functionalization in enhancing the photovoltaic and photophysical characteristics of NFAs, ultimately improving the overall performance of organic solar cells. This study advances our understanding of the structure–property relationships in NFAs and provides valuable insights into the design and optimization of organic solar cell materials. [ABSTRACT FROM AUTHOR]

This study focuses on the recognition and isolation of fullerenes, which are crucial for further exploration of their physical and chemical properties. Our goal is to investigate the potential recognition of the D5h–C70 fullerene using crown-shaped metal compositions through density functional theory calculations. We assess the effectiveness of fullerene C70 recognition by studying the binding energy. Additionally, various analyses were conducted, including natural bond order charge analysis and reduced density gradient analysis, to understand the interaction mechanism between the host and guest molecules. These investigations provide valuable insights into the nature of the interaction and the stability of the host–guest system. To facilitate the release of the fullerene guest molecule, the vis–NIR spectra were simulated for the host–guest structures. This analysis offers guidance on the specific wavelengths that can be utilized to release the fullerene guest from the host–guest structures. Overall, this work proposes a new strategy for the effective recognition of various fullerene molecules and their subsequent release from host–guest systems. These findings could potentially be applied in assemblies involving fullerenes, advancing their practical applications. [ABSTRACT FROM AUTHOR]

This study focuses on the recognition and isolation of fullerenes, which are crucial for further exploration of their physical and chemical properties. Our goal is to investigate the potential recognition of the D5h–C70 fullerene using crown-shaped metal compositions through density functional theory calculations. We assess the effectiveness of fullerene C70 recognition by studying the binding energy. Additionally, various analyses were conducted, including natural bond order charge analysis and reduced density gradient analysis, to understand the interaction mechanism between the host and guest molecules. These investigations provide valuable insights into the nature of the interaction and the stability of the host–guest system. To facilitate the release of the fullerene guest molecule, the vis–NIR spectra were simulated for the host–guest structures. This analysis offers guidance on the specific wavelengths that can be utilized to release the fullerene guest from the host–guest structures. Overall, this work proposes a new strategy for the effective recognition of various fullerene molecules and their subsequent release from host–guest systems. These findings could potentially be applied in assemblies involving fullerenes, advancing their practical applications. [ABSTRACT FROM AUTHOR]

We investigate the endofullerene system 3He@C60 with a four-dimensional potential energy surface (PES) to include the three He translational degrees of freedom and C60 cage radius. We compare second order Møller–Plesset perturbation theory (MP2), spin component scaled-MP2, scaled opposite spin-MP2, random phase approximation (RPA)@Perdew, Burke, and Ernzerhof (PBE), and corrected Hartree–Fock-RPA to calibrate and gain confidence in the choice of electronic structure method. Due to the high cost of these calculations, the PES is interpolated using Gaussian Process Regression (GPR), owing to its effectiveness with sparse training data. The PES is split into a two-dimensional radial surface, to which corrections are applied to achieve an overall four-dimensional surface. The nuclear Hamiltonian is diagonalized to generate the in-cage translational/vibrational eigenstates. The degeneracy of the three-dimensional harmonic oscillator energies with principal quantum number n is lifted due to the anharmonicity in the radial potential. The (2l + 1)-fold degeneracy of the angular momentum states is also weakly lifted, due to the angular dependence in the potential. We calculate the fundamental frequency to range between 96 and 110 cm−1 depending on the electronic structure method used. Error bars of the eigenstate energies were calculated from the GPR and are on the order of ∼±1.5 cm−1. Wavefunctions are also compared by considering their overlap and Hellinger distance to the one-dimensional empirical potential. As with the energies, the two ab initio methods MP2 and RPA@PBE show the best agreement. While MP2 has better agreement than RPA@PBE, due to its higher computational efficiency and comparable performance, we recommend RPA as an alternative electronic structure method of choice to MP2 for these systems. [ABSTRACT FROM AUTHOR]

A pseudospectral implementation of nonadiabatic derivative couplings in the Tamm–Dancoff approximation is reported, and the accuracy and efficiency of the pseudospectral nonadiabatic derivative couplings are studied. Our results demonstrate that the pseudospectral method provides mean absolute errors of 0.2%–1.9%, while providing a significant speedup. Benchmark calculations on fullerenes (Cn, n up to 100) using B3LYP achieved 10- to 15-fold, 8- to 17-fold, and 43- to 75-fold speedups for 6-31G**, 6-31++G**, and cc-pVTZ basis sets, respectively, when compared to the conventional spectral method. [ABSTRACT FROM AUTHOR]

Photomultiplication-type organic photodetectors (PM-OPDs) have been stimulating more and more researchers' interest owing to their extremely high external quantum efficiency (EQE). To prepare high-performance PM-OPDs with a broadband spectral response range from visible to near-infrared and investigate the role of energy levels of the donor and acceptor on its responsiveness, the non-fullerene acceptor Y6 was added into the P3HT:PC71BM system in this work. The photomultiplication phenomenon with the highest EQE has been achieved under both forward and reverse bias when the ratio of Y6 in two acceptors approaches 80 wt. %. The introduction of Y6 not only promotes the formation of moderate hole traps in the active layer but also results in an appropriate amount of low injection barriers to allow more electron injection from the external circuit. Therefore, the spectral response of the device with 80 wt. % Y6 has been broadened from 750 to 950 nm, and the champion EQE of 15 691% at 10 V and 7639% at −20 V at 850 nm was achieved. This work reveals the importance of hole-trapping ability determined by the energy level difference between the donor and the acceptor for the selection of the multiplication system and provides a scheme for the design of high-performance broadband PM-OPDs. [ABSTRACT FROM AUTHOR]

Four-center two-electron Coulomb integrals routinely appear in electronic structure algorithms. The resolution-of-the-identity (RI) is a popular technique to reduce the computational cost for the numerical evaluation of these integrals in localized basis-sets codes. Recently, Duchemin and Blase proposed a separable RI scheme [J. Chem. Phys. 150, 174120 (2019)], which preserves the accuracy of the standard global RI method with the Coulomb metric and permits the formulation of cubic-scaling random phase approximation (RPA) and GW approaches. Here, we present the implementation of a separable RI scheme within an all-electron numeric atom-centered orbital framework. We present comprehensive benchmark results using the Thiel and the GW100 test set. Our benchmarks include atomization energies from Hartree–Fock, second-order Møller–Plesset (MP2), coupled-cluster singles and doubles, RPA, and renormalized second-order perturbation theory, as well as quasiparticle energies from GW. We found that the separable RI approach reproduces RI-free HF calculations within 9 meV and MP2 calculations within 1 meV. We have confirmed that the separable RI error is independent of the system size by including disordered carbon clusters up to 116 atoms in our benchmarks. [ABSTRACT FROM AUTHOR]

The carbon nano-peapod is a representative structure with interlayer van der Waals (vdW) interactions, in which encapsulated fullerene molecules play a critical role in modulating the transport properties of the carbon nanotubes (CNTs). In particular, their influence on the thermal transport characteristics has been the focal point of considerable attention. In this study, we trained an accurate machine learning potential for fullerene-encapsulated CNTs based on the efficient NEP model to investigate their thermal properties. Using equilibrium molecular dynamics simulation along with the spectral decomposition method for thermal conductivity, we find that the thermal conductivity of fullerene-encapsulated CNTs is roughly 55 % lower than that of empty CNTs, aligning with experimental observations for CNT bundles with fullerene encapsulation [Kodama et al., Nat. Mater. 16, 892 (2017)]. The research suggests that weak vdW interactions between both the fullerene and CNTs, as well as between fullerene molecules themselves, hinder phonon propagation. The encapsulated fullerene contributes to an increase in phonon scattering within the CNTs, ultimately leading to a reduction in thermal conductivity. We utilized machine learning potential to investigate the structure of fullerene-encapsulated CNTs and their heat transport property. This approach provides valuable insights for performance research of complex systems featuring interlayer vdW interactions. [ABSTRACT FROM AUTHOR]

Endohedral metal–metal-bonding fullerenes have recently emerged, in which encapsulated metals form a metal–metal bond. However, the physical reasons why some metal elements prefer to form metal–metal bonds inside fullerene are still unclear. Herein, we reported first-principles calculations on electronic structures, bonding properties, dynamics, and thermodynamic stabilities of endohedral metallofullerenes M2@C82 (M = Sc, Y, La, Lu). Multiple bonding analysis approaches unambiguously reveal the existence of one two-center two-electron σ covalent metal–metal bond in M2@C82 (M = Sc, Y, Lu); however, the La–La bonding interaction in La2@C82 is weaker and could not be categorized as one metal–metal covalent bond. The energy decomposition analysis on bonding interactions between an encapsulated metal dimer and fullerene cages suggested that there exist two electron-sharing bonds between a metal dimer and fullerene cages. The reasons why La2 prefers to donate electrons to fullerene cages rather than form a standard σ covalent metal–metal bond are mainly attributed to two following facts: La2 has a lower ionization potential, while the hybridization of ns, (n − 1)d, and np atomic orbitals in La2 is higher. Ab initio molecular dynamic simulations reveal that the M–M bond length at room temperature follows the trend of Sc < Lu < Y. The statistical thermodynamics calculations at different temperatures reveal that the experimentally observed endohedral metal–metal-bonding fullerenes M2@C82 have high concentrations in the endohedral fullerene formation temperature range. [ABSTRACT FROM AUTHOR]

In light atoms, the technique of Reconstruction of Attosecond Bursts by Interference of Two-Photon Transitions (RABBITT), driven by circularly polarized radiation, enables a complete retrieval of ionization amplitudes in the XUV+IR regime, including their relative phases (Kheifets 2024 Phys. Rev. Res. 6 L012002). In this work, we extend this method to heavier atoms by conducting numerical simulations of circularly polarized RABBITT on the Kr 3 d and Xe 4 d atomic shells. The XUV ionization dynamics in these atoms differ markedly due to the presence of a 'giant' shape resonance in the 4 d → E f ionization channel of Xe, a feature absent in Kr. Nevertheless, when an IR photon is added to the XUV ionization, the results for Kr and Xe are surprisingly similar, with the ratio of absorption/emission matrix elements and their relative phases remaining close in value. Moreover, these ratios and phases show minimal variation even when the Xe atom is encapsulated within a C60 fullerene cage. In search for the Cooper-like minimum in the IR absorption amplitude ratios predicted in Ji et al (2024 J. Phys. B 57 235601), we extend our investigation to the Ce 4 f shell where this minimum is indeed present. [ABSTRACT FROM AUTHOR]

Currently, the incidence of kidney failure is increasing worldwide. Hemodialysis is the main method for the treatment of kidney diseases, and the continuous development of new hemodialysis membranes is the key to improve the treatment effect and the quality of life of patients. In this study, heparinized multi‐walled carbon nanotube/cellulose acetate (Hep/MWCNTs@CA) membranes were prepared by non‐solvent induced phase separation (NIPS). The morphology and pore structure of Hep/MWCNTs@CA membranes were characterized by scanning electron microscopy (SEM). The elongation at break and tensile strength of the membranes were characterized by a mechanical property universal tester. The results showed that mechanical properties of 0.1 wt% MWCNTs enhanced the membrane is best. The water contact angle test confirmed that MWCNTs can improve the membrane hydrophilicity, and combined with the adsorption test results for proteins, it was found that the hydrophilicity can reduce the adsorption of proteins to the composite membrane and improve the blood compatibility of the material. The dialysis performance of urea and lysozyme was tested by a self‐made simulated hemodialysis device, and the clearance rates of urea and lysozyme were 84% and 47.2%, respectively, which showed that the interfacial gap between MWCNTs and CA matrix can make the composite membrane retain a high retention rate of macromolecular proteins (92.3%) and further improved the clearance rate of small and medium molecular toxins. In addition, the good blood compatibility and biocompatible properties of the materials were confirmed by hemolysis, recalcification and cytotoxicity tests on Hep/MWCNTs@CA membranes. In conclusion, the prepared Hep/MWCNTs@CA holds great potential for application in the field of hemodialysis. [ABSTRACT FROM AUTHOR]

Carboranes are a type of molecular clusters consisting of carbon, hydrogen, and boron atoms. They possess unique characteristics, such as three-dimensional aromaticity, icosahedral geometry, and robustness. Functionalized carboranes have been utilized in various fields, including medicine, materials, and organometallic/coordination chemistry. In this context, selective functionalization of o -carboranes has received tremendous attention, specifically in the regio- and enantioselective modification of the ten chemically similar BH vertices within the carborane cage. In recent years, significant progress has been made in catalytic vertex-specific BH functionalization, as well as achieving enantioselective functionalization of the cage BH. This review provides an overview of the recent advancements in this research field. 1 Introduction 2 Carboxy-Assisted BH Functionalization 2.1 Formation of B–C Bonds 2.2 Formation of B–N Bonds 2.3 Formation of B–O Bonds 2.4 Formation of B–X Bonds 2.5 Consecutive Formation of B–C and B–Y (Y = N, O) Bonds 3 N-Based Directing-Group-Assisted B–H Functionalization 3.1 Acylamino as a Directing Group 3.2 Amide as a Directing Group 3.3 Pyridyl as a Directing Group 3.4 Imine as a Directing Group 4 Phosphinyl-Assisted Cage B–H Functionalization 5 Bidentate-Directing-Group-Assisted B–H Functionalization 6 Other Directing-Group-Assisted B–H Functionalization 7 Conclusions [ABSTRACT FROM AUTHOR]

A new approach to the topological rearrangement of the fullerene structure (ω-transformation) has recently been proposed. The further development shows that any two fullerenes of the C36–C100 variety can be structurally interconverted by a multistep ω-transformation based on moves of an octagonal defect about the fullerene surface. The addition of the Endo-Kroto operation extends the range to C24–C100. The results could be used to explain the mutual transformation of fullerenes and the synthesis possibilities of carbon structures with a given topology. [ABSTRACT FROM AUTHOR]

[Display omitted] The sluggish kinetics and inherent instability over the Ru/RuO 2 clusters are still enormous challenges in proton exchange membrane (PEM) water electrolyzer. Herein, we innovatively report synergistic modulation of dynamic electron modification and strong metal-support interaction (SMSI) to activate and stabilize bifunctional fluorine doped Ru/RuO 2 clusters anchored on carbon nanotube (CNT), thus achieving efficient and stable acidic overall water splitting. Theoretical and experimental studies found that surface metal-fluorine modification layer could dynamically regulate the interfacial electronic environment to stabilize and activate multiple active Ru species; and the SMSI between Ru/RuO 2 cluster and CNT maintains stable electronic environment for dynamic electron modification and avoids migrating or shedding of active species in acidic environment. Therefore, the PEM electrolyzer assembled with optimal F 5.5 -Ru/RuO 2 @CNT can operate stably for 100 h at a high current density of 100 mA cm−2, which is the first time that bifunctional Ru-based nanocatalysts applied to PEM device at a high current density. [ABSTRACT FROM AUTHOR]

Purpose: Due to the close connection between urban cluster and carbon emissions (CEs) but a lack of study on it of the construction industry, this paper aims to explore the relationship between the polycentric spatial structure (PSS) of the urban clusters and CEs of the construction industry (CECI). Design/methodology/approach: This research uses panel data of 10 Chinese urban clusters from 2006–2021, calculates their PSSs in the aspects of economy and employment and adopts a panel regression model to explore the effect of the spatiotemporal characteristics of the PSSs on the CECI. Findings: First, the CECI in 10 Chinese urban clusters showed a rising trend in general, and the CECI in the Yangtze River Delta (YRD) was much higher than those in the rest of urban clusters. Second, both Shandong Peninsula (SP) and Guangdong-Fujian-Zhejiang (GFZ) exhibited high degrees of polycentric characteristics, while Beijing-Tianjin-Hebei (BTH) showed weaker degrees. Third, the results demonstrated that the polycentric development of urban clusters did not help reduce the CECI but rather promote the CE. The polycentric index, considering the linear distance from the main center to sub center, had a more significant impact on the CECI. Originality/value: Previous studies have investigated the impact of urban spatial structure (USS) on CEs; however, few of them have studied in the field of construction industry. Moreover, most research of CEs have concentrated at the national and provincial levels, with fewer studies on urban clusters. This paper contributes to this knowledge by investigating how the PSS of urban cluster influence the CECI. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu clusters with the diameter of ∼1.0 nm was fabricated and coordinated with B, N atoms in porous carbon matrix. • The catalyst showed stable 70 % FE under 20.8 mA cm−2 during 12 h testing in CO 2 RR to formate. • The overall catalytic performance of Cu/BN-C was superior to other Cu-based catalysts. • DFT revealed the synergy between Cu clusters and B, N by enhancing the charge density of Cu. • This research highlighted the importance of synergistic effects of Cu size effect and heteroatoms coordination. Electrochemical CO 2 conversion into formate by intermittent renewable electricity, presents a captivating prospect for both the storage of renewable electrical energy and the utilization of emitted CO 2. Typically, Cu-based catalysts in CO 2 reduction reactions favor the production of CO and other by-products. However, we have shifted this selectivity by incorporating B, N co-doped carbon (BNC) in the fabrication of Cu clusters. These Cu clusters are regulated with B, N atoms in a porous carbon matrix (Cu/BN-C), and Zn2+ ions were added to achieve Cu clusters with the diameter size of ∼1.0 nm. The obtained Cu/BN-C possesses a significantly improved catalytic performance in CO 2 reduction to formate with a Faradaic efficiency (FE) of up to 70 % and partial current density (j formate) surpassing 20.8 mA cm−2 at −1.0 V vs RHE. The high FE and j formate are maintained over a 12-hour. The overall catalytic performance of Cu/BN-C outperforms those of the other investigated catalysts. Based on the density functional theory (DFT) calculation, the exceptional catalytic behavior is attributed to the synergistic effect between Cu clusters and N, B atoms by modulating the electronic structure and enhancing the charge transfer properties, which promoted a preferential adsorption of HCOO* over COOH*, favoring formate formation. [ABSTRACT FROM AUTHOR]

Hydrogen technologies for manufacturing solar-hydrogen energy systems are advancing rapidly, focusing on creating sustainable and efficient methods to produce green hydrogen. Here are some key technologies and approaches: 1. Photoelectrochemical (PEC) Systems: These systems combine photovoltaic devices with electrolyzers. The photovoltaic device absorbs sunlight and generates electricity, which then drives the electrolytic splitting of water into hydrogen and oxygen. This integrated approach can be more cost-effective and efficient. 2. Photocatalytic (PC) Water Splitting: This method uses photocatalysts to directly harness sunlight to split water molecules. It's a promising approach but still faces challenges in efficiency and scalability. 3. Solar-to-Hydrogen Pilot Plants: Recent developments include kilowatt-scale pilot plants that use concentrated solar power to produce hydrogen. 4. Hydrogels for Artificial Photosynthesis: Innovative materials like bioinspired hydrogels are being developed to mimic natural photosynthesis, using sunlight to produce hydrogen and oxygen from water. 1. Photoelectrochemical (PEC) Systems: These systems combine photovoltaic devices with electrolyzers. The photovoltaic device absorbs sunlight and generates electricity, which then drives the electrolytic splitting of water into hydrogen and oxygen. This integrated approach can be more cost-effective and efficient. 2. Photocatalytic (PC) Water Splitting: This method uses photocatalysts to directly harness sunlight to split water molecules. It's a promising approach but still faces challenges in efficiency and scalability. 3. Solar-to-Hydrogen Pilot Plants: Recent developments include kilowatt-scale pilot plants that use concentrated solar power to produce hydrogen. 4. Hydrogels for Artificial Photosynthesis: Innovative materials like bioinspired hydrogels are being developed to mimic natural photosynthesis, using sunlight to produce hydrogen and oxygen from water. These technologies aim to create a sustainable hydrogen production process, reducing reliance on fossil fuels and minimizing carbon emissions. The results of studies of the physical properties of hydrogenated amorphous thin films of a − Si 1 − x Ge x : H and a − Si 1 − x C x : H , alloys obtained by plasma-chemical deposition are presented. The optical constants (n , n 1 , α , R , d) and the band gap of the films under study (E 0 = 1.05 ÷ 3.00 eV) were determined. Based on a study of the optical properties of various deposition modes (T sub , d , H 2), the substrate temperature, film thickness and level of hydrogenation of the alloys are characterized by different structural phases. (With a change in technological parameters, various structural phases of crystallites are also obtained: nanotubes, nanowires, nanoparticles, quantum wells, quantum dots, graphenes, graphites, decanters, fullerenes, diamond particles, clusters, and others) and polymer phases. The structure of the deposited nc-Si:H films is mixed-two-phase and consists of nc-Si:H nanocrystallites « distributed» in an amorphous network. Annealing of crystalline films at a temperature of 700 °C increases the crystallite size to 50 ÷ 100A° in diameter, and the conductivity changes slightly. Also, when hydrogen is introduced into an amorphous silicon film at low temperatures (Т s ≤100 °C) with a higher hydrogen content (∼30 atm.% or more), the material contains an excess of the SiH 3 group, as well as slightly more hydrogen in polymer form (SiH 2) n. The concentration of carbon and hydrogen in a − Si 1 − x C x : H films depends on the deposition conditions and the initial gas mixture SiH 4 , CH 4 , H 2. Depending on the choice of modes with increasing concentrations of hydrogen, CH 4 and H 2 , the film is deposited in polymer form. SOLAR-HYDROGEN ENERGY.(provided to the authors on November 26, 2024 for printing in IJHE from the archive of Fermaltech Montenegro Limited, made by A.L. Gusev using Designer. On the DALL E 3 platform.). [Display omitted] [ABSTRACT FROM AUTHOR]

Since its conceptualization, click chemistry in all its variants has proven to be a superior synthesis protocol, compared to conventional methods, for forming new covalent bonds under mild conditions, orthogonally, and with high yields. If a term like reactive resilience could be established, click reactions would be good examples, as they perform better under increasingly challenging conditions. Particularly, highly hindered couplings that perform poorly with conventional chemistry protocols—such as those used to conjugate biomacromolecules (e.g., proteins and aptamers) or multiple drugs onto macromolecular platforms—can be more easily achieved using click chemistry principles, while also promoting high stereoselectivity in the products. In this review, three molecular platforms relevant in the field of nanomedicine are considered: polymers/copolymers, cyclodextrins, and fullerenes, whose functionalization poses a challenge due to steric hindrance, either from the intrinsic bulk behavior (as in polymers) or from the proximity of confined reactive sites, as seen in cyclodextrins and fullerenes. Their functionalization with biologically active groups (drugs or biomolecules), primarily through copper-catalyzed azide–alkyne cycloaddition (CuAAC), strain-promoted azide–alkyne cycloaddition (SPAAC), inverse electron-demand Diels–Alder (IEDDA) and thiol–ene click reactions, has led to the development of increasingly sophisticated systems with enhanced specificity, multifunctionality, bioavailability, delayed clearance, multi-targeting, selective cytotoxicity, and tracking capabilities—all essential in the field of nanomedicine. [ABSTRACT FROM AUTHOR]

Encapsulations of carbon dioxide into D 2 (22)- C 84 and D 2 d (23)- C 84 fullerenes are evaluated. The encapsulation energy is computed with the DFT M06-2X/6-31+ G * approach corrected for the basis set superposition error evaluated by the counterpoise method. The resulting encapsulation energy for CO 2 @ D 2 (22)- C 84 and CO 2 @ D 2 d (23)- C 84 amounts to substantial values of −14.5 and −13.9 kcal/mol, respectively. The energy gain is slightly larger than for CO@ C 60 , already synthesized with a high-temperature and high-pressure treatment—so that a similar preparation of CO 2 @ C 84 could be possible. The calculated rotational constants and IR vibrational spectra are presented for possible use in detection. The stability of (CO 2) 2 @ C 84 is also briefly discussed. [ABSTRACT FROM AUTHOR]

In this work, within the framework of a self-consistent model of arc discharge, a simulation of plasma parameters in a mixture of argon and methane was carried out, taking into account the evaporation of the electrode material in the case of a refractory and non-refractory cathode. It is shown that in the case of a refractory tungsten cathode, almost the same methane conversion rate is observed, leading to similar values in the density of the main methane conversion products (C, C2, H) at different values of the discharge current density. However, with an increase in the current density, the evaporation rate of copper atoms from the anode increases, and a jump in the I–V characteristic is observed, caused by a change in the plasma-forming ion. This is due to the lower ionization energy of copper atoms compared to argon atoms. In this mode, an increase in metal–carbon nanoparticles is expected. It is shown that, in the case of a cathode made of non-refractory copper, the discharge characteristics and the component composition of the plasma depend on the field enhancement factor near the cathode surface. It is demonstrated that increasing the field enhancement factor leads to more efficient thermal field emission, lowering the cathode's surface temperature and the gas temperature in the discharge gap. This leads to the fact that, in the arc discharge mode with a cathode made of non-refractory copper, the dominant types of particles from which the synthesis of a nanostructure can begin are, in descending order, copper atoms (Cu), carbon clusters (C2), and carbon atoms (C). [ABSTRACT FROM AUTHOR]

Context: In this work, we have studied different properties of a series of fullerenes, from C24 to C50 by confining hydrogen molecule inside their cavity. The compression of the hydrogen molecule upon encapsulation is evidenced by its altered bond length, while a slight expansion of the fullerene cages due to H2 confinement is also noted. The chemical reactivity parameters of both the empty and H2 confined fullerenes are computed, alongside an examination of the energy components through energy decomposition analysis. Analysis of the absorption spectra indicated that both H2 encapsulated and empty fullerenes exhibited absorption in the UV region. Nevertheless, the inclusion of H2 within the fullerene cages appeared to have minimal influence on the reactivity parameters and absorption spectra, as evidenced by the comparison between the sets of empty and H2-confined fullerenes. Methods: The computational work including the geometry optimization, followed by the frequency analysis and other parameters has been achieved using Gaussian09 software. For doing these calculations, B3LYP and CAM-B3LYP functionals along with 6–311 + G(d,p) basis set is used. In addition, MULTIWFN software has been considered for studying bonding analysis and energy decomposition analysis for the systems. [ABSTRACT FROM AUTHOR]

The digitization process plays a crucial role in eliminating tourism's "low efficiency" developmental pitfall and addressing the conflict between high-caliber tourism development and the reduction of carbon emissions. The study quantified carbon emissions from tourism in the Yangtze River Economic Belt of China using both the carbon footprint and the "bottom-up" approach and developed a panel threshold model to empirically evaluate the nonlinear effect of the digital economy on tourism carbon emissions. The results show that the effect of the digital economy on carbon emissions in tourism will vary in structure depending on the degree of tourist concentration and the concentration of residents in tourist areas. Particularly, considering varying levels of tourism concentration and the resident population density, the overall impact of the digital economy on carbon emissions from tourism exhibits a reversed "V" type single threshold characteristic. If the concentration of the tourism sector falls below 1.08 or its resident population density is under 389.9, digital tourism growth exacerbates carbon emissions, resulting in incremental impacts of 3.3 and 2.38, respectively. If the concentration of the tourism sector exceeds 1.08 or its resident population density surpasses 389.90, the collective impact of digital tourism growth will be maximized, and advancing the digital economy will aid in lowering carbon emissions in the tourism sector, yielding incremental impacts of -3.94 and -2.17, respectively. The impact of the digital economy on diminishing carbon emissions within the tourism sector primarily focuses on transportation and tourism-related activities. Achieving a harmonious interplay between tourism's digital evolution and the reduction of carbon emissions requires not only the focused growth of the digital economy, but also the strategic direction of tourism businesses and the concentration of populations, thereby disrupting the inflexible trend of tourism carbon emissions clustering. [ABSTRACT FROM AUTHOR]

Urbanization and its impact on land use and land cover change are key drivers of global carbon balance shifts. Understanding the spatiotemporal evolution of carbon balance in relation to urbanization helps optimize regional planning and sustainable development. This study develops a city-level land use carbon balance system to quantify the spatiotemporal dynamics of land use carbon balance across 130 cities in the Yangtze River Economic Belt (YREB). Moran's Index is applied to assess the spatial correlation of carbon balance, and the Environmental Kuznets Curve (EKC) is used to explore the relationship between urbanization levels and net carbon emissions. The results show the following: (1) From 2005 to 2021, land use carbon absorption in YREB cities remained relatively stable, whereas carbon emissions increased. Net carbon emissions increased by 574.61, 456.16, and 1163.60 Mt C in the upper, middle, and lower reaches, respectively. Nearly 98% of the cities exhibited a carbon balance index greater than 1, indicating a carbon deficit. Carbon emission intensity displayed a decreasing trend, with the most significant reductions observed in the middle reaches. (2) Land use carbon balance exhibits significant positive spatial correlation, with cities in the northeastern lower reaches and southwestern upper reaches forming "high–high" and "low–low" net carbon emission clusters. (3) Urbanization and per capita net carbon emissions followed an inverted "N"-shaped curve, with turning points at around 30% and 85% urbanization. This study provides insights into optimizing land use carbon management amidst urban growth in the YREB. [ABSTRACT FROM AUTHOR]

Since the discovery of La@C82, a wide array of endohedral metallofullerenes (EMFs) have been synthesized and documented. Various metals, including lanthanides, transition metals, alkali metals, alkaline earth metals and actinides, have been successfully incorporated into the inert fullerene cavities. The interaction between these encapsulated metal species and the fullerene cage isomers plays a crucial role in determining distinct molecular structures and imparting versatile chemical behaviors to these compounds. In particular, recent advancements in EMFs with medium-sized carbon cages, which are among the most versatile categories of EMFs, have marked a significant breakthrough in fundamental coordination chemistry and opened up a wide range of potential applications. The formation of various abnormal metal clusters, possessing unique chemical bonding character and geometric conformations, has been shown to be influenced by novel electron transfer mechanisms between the metal atoms and the carbon cage. Moreover, these specialized metal–cage interactions have also facilitated the stabilization of giant fullerene families and promoted the exploration of these structures in greater detail, particularly with respect to the unanticipated metallofullertubes. Therefore, this review aims to highlight the new phenomena arising from these novel metal–cage interactions in the fundamental study of pristine EMFs. On this basis, we also discussed innovative applications of EMF-based supramolecular complexes that stem from their unique host–guest association. [ABSTRACT FROM AUTHOR]

ABSTRACT Activated carbon injection technology is the primary method used to control the mercury emissions from coal‐fired power plants. The preparation of sulfur‐loaded carbon‐based adsorbents through SO2 modification of the surface of activated carbon (the primary component) provides an effective solution to enhancing the mercury removal performance of adsorbents. However, there remains a lack of clarity on the adsorption performance and mechanism of mercury on the newly formed active sites of the carbon surface after SO2 sulfur loading modification. In this study, four potential structures of SO2 loaded onto the surface of activated carbon were constructed. Quantum chemical calculation methods were applied to calculate the adsorption process of Hg in these four models, with those important characteristics identified such as bonding properties, adsorption energy, electrostatic potential, and molecular orbitals. As indicated by those results, the adsorption bonds of the SO2‐modified activated carbon were mainly C‐O‐S and C‐S‐C. After the carbon cluster model adsorbed SO2 molecules, the sulfur in SO2 exhibited a strong positive potential that facilitated the loss of electrons from Hg due to the potential difference. Consequently, HgO was firmly adsorbed onto the surface of the carbon cluster. As revealed by the molecular orbital calculations performed after Hg adsorption on the two carbon cluster models, SO2‐modified and elemental sulfur‐modified activated carbons, in the SOAC‐Arm‐1 configuration, there was a clear exchange orbital around the adsorbed Hg atom in the LUMO, with a small HOMO–LUMO energy gap of only 0.01713 eV. At this point, the free electrons on the molecule were prone to orbital transitions, promoting the occurrence of adsorption reactions. The SOAC‐Arm‐3 conformation exhibited the shortest C‐Hg bond length and had an adsorption energy of up to −70.42 kJ/mol, indicating a stronger chemical bonding ability and a higher likelihood of adsorption reactions. These results demonstrate the feasibility of sulfur‐loaded modified activated carbon to mitigate Hg pollution through SO2. [ABSTRACT FROM AUTHOR]

The induction of chirality on pristine fullerenes through non‐covalent embedding in an asymmetric nano‐confinement has only been rarely reported. Bringing molecules with such a unique electronic structure and broad application range into a chiral environment is particularly appealing for the development of chiroptical materials, enantioselective photoredox catalysts and systems showing chirality‐induced spin selectivity (CISS). In this study, we report the formation of a chiral, configurationally stable Pd2L4 capsule assembled from a C2‐symmetric, ‘ribbon‐shaped’ ligand with a Tröger's base naphthalimide (TbNaps) backbone, easily synthesized in three steps from commercially available compounds. Embedding chirality directly into the ligand backbone ensures a relatively lightweight receptor design whose aromatic panels create a strongly shielded inner cavity of about 700 Å3 volume. Fullerenes C60 and C70, as well as a pair of corannulenes, can be bound in acetonitrile (where unsubstituted fullerenes are insoluble) and X‐ray structures of host‐guest complexes were obtained. Tight interactions between the chiral host and the fullerene guests leads to the induction of a circular dichroism (CD) on the characteristic absorption bands of the forbidden π–π* transitions of the fullerenes, backed up by sTDA TD‐DFT calculations and detailed investigation of the electronic excited states. [ABSTRACT FROM AUTHOR]

The paper compares two methods of the carbon fiber surface cleaning for their following modification and more complete realization of its physical and mechanical properties. The aim of the work is to identify the optimal method of pre-modification of carbon fiber, which in the future will be used as a filler of polymer binder in the composite. The results demonstrate successful surface cleaning, preservation of the level of physical and mechanical properties of fibers, increase of capillarity index. [ABSTRACT FROM AUTHOR]

Context: Battery interface research can effectively guide battery design and material selection to improve battery performance. However, current electrode material interface studies still have significant limitations. In this paper, by employing DFT-D method, the influences of doping elements (boron, nitrogen, phosphorus, sulfur, and silicon) on the properties of C60 fullerene, such as structural stability, electronic properties, and the adsorption and migration of lithium ion, are comprehensively investigated. It is demonstrated that doping can bolster the fullerene molecule's structural integrity and enhance charge transfer comparing with C60, thereby augmenting the material's electrical conductivity. Among the five doping elements, B-doping exhibits the most favorable adsorption energies, indicating a strong lithium binding affinity. This observation is supported with energy barrier of lithium ion migration. B-doping leads to an elevated barrier (0.37 eV) comparing with pristine C60 (0.19 eV), whereas Si-doping significantly reduced barrier (0.038 eV) indicates enhanced lithium-ion mobility. These findings solid the efficacy of doping as a strategy to enhance the performance of fullerene electrodes. Method: All DFT calculations were performed using the VASP software package. The chosen computational technique was a combination of the generalized approximate gradient function PBE with the dispersion correction (DFT-D3) developed by Grimme. The results of the calculations were analyzed with the help of VASPKIT. [ABSTRACT FROM AUTHOR]

The effect of fluorination of boron nitride fullerene B12N12 on its activity towards the favipiravir molecule (a drug against the COVID-19 virus) is studied by the density functional theory. Two types of fullerene fluorination are considered: external doping with the formation of the B12N12F2 structure and endohedral doping with the formation of the F–@B12N12 complex. It is shown that fluorinated clusters can attach favipiravir by the same mechanism as initial fullerene. It is found that the interaction between the drug and the endohedral complex is too weak, while external doping by fluorine increases the binding energy between the cluster and the drug. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) causes multiple cerebrovascular disruptions and oxidative stress. These pathological mechanisms are often accompanied by serious impairment of cerebral blood flow autoregulation and neuronal and glial degeneration. Background/Objectives: Multiple biochemical cascades are triggered by brain damage, resulting in reactive oxygen species production alongside blood loss and hypoxia. However, most currently available early antioxidant therapies lack capacity and hence sufficient efficacy against TBI. The aim of this study was to test a novel catalytic antioxidant nanoparticle to alleviate the damage occurring in blast TBI. Methods: TBI was elicited in an open blast rat model, in which the rats were exposed to the effects of an explosive blast. Key events of the post-traumatic chain in the brain parenchyma were studied using immunohistochemistry. The application of a newly developed biologically compatible catalytic superoxide dismutase mimetic carbon-based nanocluster, a poly-ethylene-glycol-functionalized hydrophilic carbon cluster (PEG-HCC), was tested post-blast to modulate the components of the TBI process. Results: The PEG-HCC was shown to significantly ameliorate neuronal loss in the brain cortex, the dentate gyrus, and hippocampus when administered shortly after the blast. There was also a significant increase in endothelial activity to repair blood–brain barrier damage as well as the modulation of microglial and astrocyte activity and an increase in inducible NO synthase in the cortex. Conclusions: We have demonstrated qualitatively and quantitatively that the previously demonstrated antioxidant properties of PEG-HCCs have a neuroprotective effect after traumatic brain injury following an explosive blast, acting at multiple levels of the pathological chain of events elicited by TBI. [ABSTRACT FROM AUTHOR]

Curved π‐electron systems show unique properties and assembly feature that enable the specific applications in materials science and supramolecular chemistry. Herein, fullerene, carbon nanohoop and π‐bowl are integrated by the coupling of covalent and supramolecular tactics. Firstly, π‐bowl trichalcogenasumanenes (TCSs) are fused with a carbon nanohoop [10]CPP via covalent joint to form molecular crowns 4a/4b, which show structural and electronic complementarity and accordingly strong binding affinity to C60/C70. Secondly, the supramolecular assemblies of 4a/4b with fullerenes afford the host‐guest complexes 4a/4b⊃C60/C70 in solution (molar ratio, 2:1) and solid state (molar ratio, 1:1). In the crystals of host–guest complexes, the intra‐cluster and inter‐cluster interactions are respectively dominated by the [10]CPP and TCSs moieties of 4a/4b. Additionally, it is found that 4a/4b are good photosensitizers for generating 1O2 and show structural adaptability in accordance to assembly conditions. 4a/4b take an endo‐conformation in their own crystals with TCSs and [10]CPP moieties being bowl‐shaped and elliptical, respectively. In contrast, the [10]CPP on 4a/4b changes into circular and the TCSs moiety becomes flat (for 4b) or shows bowl inversion to be exo‐conformation (for 4a) in 4a/4b⊃C60/C70. [ABSTRACT FROM AUTHOR]

Non-fullerene electron acceptors have emerged as promising alternatives to traditional electron-acceptors in the active layers of organic photovoltaics. This is due to their tunable energy levels, optical response in the visible light spectrum, high electron mobility, and photochemical stability. In this study, the electronic properties of two representative non-fullerene acceptors, ITIC and Y5, have been calculated within the framework of density functional theory using a range of hybrid and non-hybrid density functionals. Screened range-separated hybrid (SRSH) approaches were also tested. The results are analyzed in light of the previously reported experimental outcomes. Specifically, we have calculated the oxidation and reduction potentials, fundamental and optical gaps, the highest occupied molecular orbital and lowest unoccupied molecular orbital energies, and exciton binding energies. Additionally, we have investigated the effects of the medium dielectric constant on these properties employing a universal implicit solvent model. It was found that hybrid functionals generally perform poorly in predicting oxidation potentials, while non-hybrid functionals tend to overestimate reduction potentials. The inclusion of a large Hartree–Fock contribution to the global or long range was identified as the source of inaccuracy for many hybrid functionals in predicting both redox potentials and the fundamental and optical gaps. Corroborating with the available literature, ∼50% of all tested functionals predicted very small exciton binding energies, within the range of ±0.1 eV, that become even smaller by increasing the dielectric constant of the material. Finally, the OHSE2PBE and tHCTHhyb functionals and the optimal tuning SRSH approach emerged as the best-performing methods, with good accuracy in the description of the electronic properties of interest. [ABSTRACT FROM AUTHOR]

GeSnC alloys offer a route to direct bandgap semiconductors for CMOS-compatible lasers, but the use of CBr4 as a carbon source was shown to reduce Sn incorporation by 83%–92%. We report on the role of thermally cracked H in increasing Sn incorporation by 6x–9.5x, restoring up to 71% of the lost Sn, and attribute this increase to removal of Br from the growth surface as HBr prior to formation of volatile groups such as SnBr4. Furthermore, as the H flux is increased, Rutherford backscattering spectroscopy reveals a monotonic increase in both Sn and carbon incorporation. X-ray diffraction reveals tensile-strained films that are pseudomorphic with the substrate. Raman spectroscopy suggests substitutional C incorporation; both x-ray photoelectron spectroscopy and Raman suggest a lack of graphitic carbon or its other phases. For the lowest growth temperatures, scanning transmission electron microscopy reveals nanovoids that may account for the low Sn substitutional fraction in those layers. Conversely, the sample grown at high temperatures displayed abrupt interfaces, notably devoid of any voids, tin, or carbon-rich clusters. Finally, the surface roughness decreases with increasing growth temperature. These results show that atomic hydrogen provides a highly promising route to increase both Sn and C to achieve a strongly direct bandgap for optical gain and active silicon photonics. [ABSTRACT FROM AUTHOR]

Endohedral fullerenes, or endofullerenes, are chemical systems of fullerene cages encapsulating single atoms or small molecules. These species provide an interesting challenge of Potential Energy Surface determination as examples of non-covalently bonded, bound systems. While the majority of studies focus on C60 as the encapsulating cage, introducing some anisotropy by using a different fullerene, e.g., C70 can unveil a double well potential along the unique axis. By approximating the potential as a pairwise Lennard-Jones (LJ) summation over the fixed C cage atoms, the parameter space of the Hamiltonian includes three tunable variables: (M, ɛ, σ) representing the mass of the trapped species, the LJ energy, and length scales respectively. Fixing the mass and allowing the others to vary can imitate the potentials of endohedral species trapped in more elongated fullerenes. We choose to explore the LJ parameter space of an endohedral atom in C70 with ɛ ∈ [20, 150 cm−1], and σ ∈ [2.85, 3.05 Å]. As the barrier height and positions of these wells vary between [1, 264 cm−1] and [0.35, 0.85 Å] respectively, using a 3D direct product basis of 1D harmonic oscillator (HO) wavefunctions centred at the origin where there is a local maximum is unphysical. Instead we propose the use of a non-orthogonal basis set, using 1D HO wavefunctions centred in each minimum and compare this to other choices. The ground state energy of the X@C70 is tracked across the LJ parameter space, along with its corresponding nuclear translational wavefunctions. A classification of the wavefunction characteristics, namely the prolateness and "peanut-likeness" based on its statistical moments is also proposed. Excited states of longer fullerenes are assigned quantum numbers, and the fundamental transitions of Ne@C70 are tracked across the parameter space. [ABSTRACT FROM AUTHOR]

We present a many-body GW formalism for quantum subsystems embedded in discrete polarizable environments containing up to several hundred thousand atoms described at a fully ab initio random phase approximation level. Our approach is based on a fragment approximation in the construction of the Green's function and independent-electron susceptibilities. Further, the environing fragments susceptibility matrices are reduced to a minimal but accurate representation preserving low order polarizability tensors through a constrained minimization scheme. This approach dramatically reduces the cost associated with inverting the Dyson equation for the screened Coulomb potential W, while preserving the description of short to long-range screening effects. The efficiency and accuracy of the present scheme is exemplified in the paradigmatic cases of fullerene bulk, surface, subsurface, and slabs with varying number of layers. [ABSTRACT FROM AUTHOR]

In this contribution, we employ computational tools from the energy landscape approach to test Gaussian Approximation Potentials (GAPs) for C60. In particular, we apply basin-hopping global optimization and explore the landscape starting from the low-lying minima using discrete path sampling. We exploit existing databases of minima and transition states harvested from previous work using tight-binding potentials. We explore the energy landscape for the full range of structures and pathways spanning from the buckminsterfullerene global minimum up to buckybowls. In the initial GAP model, the fullerene part of the landscape is reproduced quite well. However, there are extensive families of C1@C59 and C2@C58 structures that lie lower in energy. We succeeded in refining the potential to remove these artifacts by simply including two minima from the C2@C58 families found by global landscape exploration. We suggest that the energy landscape approach could be used systematically to test and improve machine learning interatomic potentials. [ABSTRACT FROM AUTHOR]

In this contribution, we employ computational tools from the energy landscape approach to test Gaussian Approximation Potentials (GAPs) for C60. In particular, we apply basin-hopping global optimization and explore the landscape starting from the low-lying minima using discrete path sampling. We exploit existing databases of minima and transition states harvested from previous work using tight-binding potentials. We explore the energy landscape for the full range of structures and pathways spanning from the buckminsterfullerene global minimum up to buckybowls. In the initial GAP model, the fullerene part of the landscape is reproduced quite well. However, there are extensive families of C1@C59 and C2@C58 structures that lie lower in energy. We succeeded in refining the potential to remove these artifacts by simply including two minima from the C2@C58 families found by global landscape exploration. We suggest that the energy landscape approach could be used systematically to test and improve machine learning interatomic potentials. [ABSTRACT FROM AUTHOR]