Energy Difference Research Articles

Microscopic insights into effects of sulfolane additive on Li–S battery electrolyte

Lithium–sulfur (Li–S) batteries, which have a high theoretical capacity and can be prepared using low-cost activation materials, are a promising alternative for realizing high-energy-density battery systems. However, the stability of the electrolyte and the shuttle effect caused by dissolved lithium polysulfides in the electrolyte prevent their practical application. Due to its non-flammability and high oxidation stability, sulfolane shows good promise for improving the oxidation stability and weakening the shuttle effect of Li–S electrolytes. In this work, the effects of a sulfolane additive on a Li–S battery electrolyte were revealed by density functional theory calculations and molecular dynamics simulations. The molecular orbitals, thermodynamics, and dynamics of the oxidation reaction were analyzed from the electron level. The addition of sulfolane lowers the HOMO energy level and the configuration energy difference, which leads to improved oxidation stability. Furthermore, sulfolane shows affinity to the S atoms close to Li, which correspond to low-order polysulfides. This affinity is confirmed by binding energy data and indicates that the addition of sulfolane inhibits the diffusion of Li2S4, Li2S6 and Li2S8. This work provides an analysis of the effects of sulfolane as an additive from the electron and molecular levels, which will promote a better understanding of Li–S battery systems and enable the design of improved electrolytes.

Uncovering a general oxidation model of nitrogen-containing oxidant in N-heterocyclic carbene (NHC) catalyzed oxidative reactions of aldehydes

Predicting how oxidants interact with reactive partners to alter the oxidation mechanism is a significant challenge in carbene catalysis. In this study, we investigated several examples to address this issue. Using density functional theory (DFT), we explored N-heterocyclic carbene (NHC)-catalyzed oxidative [2 + 4] annulations of aliphatic aldehydes with α,β-unsaturated ketones, focusing on the role of nitrogen-containing oxidant. Our computational results reveal that a hydrogen-bonding bridge framework, formed during oxidation, is crucial for facilitating π···π stacking interactions between the oxidant and the NHC catalyst. These interactions significantly lower the oxidation energy barrier, enabling a facile hydride transfer. This mechanism was validated across other reactions involving different nitrogen-containing oxidants. Frontier molecular orbital (FMO) analysis demonstrates how the NHC catalyst lowers the cycloaddition energy barrier by altering the orbital overlap from shoulder-to-head to head-to-head. Additionally, this elucidates the origin of stereoselectivity by highlighting energy differences between two reacting components at cycloaddition transition states. The nucleophilic index further predicts the preferred ketone attack site. This work advances our understanding of oxidation mechanisms involving nitrogen-containing oxidants and offers valuable insights for designing potent organic oxidants in organocatalytic oxidative reactions.

Towards the accurate simulation of multi-resonance emitters using mixed-reference spin-flip time-dependent density functional theory

Multi-resonant Thermally Activated Delayed Fluorescent (MR-TADF) materials have received significant research interest owing to their potential use as emitters in high-performance Organic Light Emitting Diodes (OLEDs). Despite their advantages, including narrow emission spectra leading to high colour purity, several challenges remain in optimising the performance of these materials. One key issue is the typically long delayed fluorescence lifetime which arises from a large gap and weak coupling between the lowest lying singlet and triplet states. To develop high-performing materials, in silico design is an important step and consequently it is crucial to develop and deploy computational methods that accurately model their excited state properties. Previous studies have highlighted the importance of double excitations, which are not accounted for within the framework of Linear Response Time-Dependent Density Functional Theory (LR-TDDFT), contributing to the poor performance of this method for these materials. Consequently, in this work, we employ Mixed-Reference Spin-Flip Time-Dependent Density Functional Theory (MRSF-TDDFT) to calculate the properties of MR-TADF materials. Our findings indicate that this approach accurately predicts the excited state properties including the crucial ΔEST, the energy difference between the lowest singlet (S1) and triplet (T1) excited states. We further use this method to explore the excited state properties of systems designed to enhance the coupling between singlet and triplet states by increasing the density of states and enhancing spin–orbit coupling through metal perturbation. The results in this work sets the foundation for computationally efficient in silico development high-performing MR-TADF materials within the framework of MRSF-TDDFT.

Study on the role of alkali halides on the mutarotation and dehydration of d-xylose in aqueous solution

Although the xylose mutarotation and transformation have been investigated largely separately, their relationship has been rarely systematically elaborated. The effect of several factors such as xylose concentration, temperature, and salt concentration, affecting the mutarotation of xylose are discussed. Nine alkali halides (LiCl, NaCl, KCl, LiBr, NaBr, KBr, LiI, NaI, and KI) are used to test salt effects. The relationship between xylose rotation rate constant (kM), specific optical rotation at equilibrium ([α]eqm), α/β ratio, H chemical shift difference (ΔΔδ), Gibbs free energy difference (ΔG), hydrogen ion or hydroxide ion concentration ([H+] or [OH−]), and xylose conversion is discussed. Different salts dissolved in water result in different pH of the solutions, which affect the mutarotation of xylose, with the nature of both cation and anion. Shortly, the smaller the cation radius is and the larger the anion radius is, the greater the mutarotation rate is. In the dehydration of xylose to furfural in salty solutions, xylose conversion is positively correlated to mutarotation rate, H+ or OH− concentration, and the energy difference between α-xylopyranose and β-xylopyranose. Although the [α]eqm of xylose is positively correlated with α/β configuration ratio, there is no obvious correlation with xylose dehydration. The conversion to furfural in chlorides is superior to that in bromines and iodides, which is due to the fact that the pH of chloride salts is smaller than that of the corresponding bromide and iodized salts. Higher H+ concentration prefers to accelerate the formation of furfural. In basic salt solutions, the xylulose selectivity is higher than that of furfural at the initial stage of reaction. The furfural selectivity and carbon balance are better in acidic condition rather than in basic condition. In H2O-MTHF (2-Methyltetrahydrofuran) biphasic system, the optimal furfural selectivity of 81.0 % is achieved at 190 °C in 1 h with the assistance of LiI and a little HCl (0.2 mmol, 8 mmol/L in aqueous phase). A high mutarotation rate represents rapid xylose conversion, but a high furfural selectivity prefers in acidic solutions, which would be perfect if organic solvents were available to form biphasic systems.

Effect of Cl2 Radical on Dry Development of Spin-Coated Metal Oxide Resist.

In this study, the effects of Cl2 radicals on dry development of spin-coated metal oxide resist (MOR) and changes in its surface binding states were investigated to verify the mechanism of dry development. Dry development characteristics of tin hydroxide (Tin OH), which is one of the MOR candidates for next generation lithography, were investigated as functions of process time and temperature using a Cl2 radicals source. Non-UV-exposed Tin OH film showed a linear etch rate (1.77 nm/min) from the initial thickness of ∼50 nm, while the UV-exposed film showed slower etch behavior (1.46 nm/min) in addition to the increase of film thickness for up to 3 min during the Cl2 radical dry development. UV-exposed photoresist (PR) contained more oxygen (Sn-O bonding) in the film due to the removal of butyl compounds from the clusters during the UV exposure process. Therefore, due to the lower reaction of chlorine radicals with Sn-O in the UV-exposed Tin OH than the other bindings, the non-UV-exposed PR was preferentially removed compared to the UV-exposed PR. As the temperature decreases, the overall etch rate decreases, but the difference in etch rate between exposed and unexposed Tin OH becomes larger. Finally, at a substrate temperature of -20 °C, the non-UV-exposed Tin OH with a thickness of 50 nm was completely removed, while ∼30 nm thick PR remained for UV-exposed Tin OH. Eventually, a negative tone development was possible with Cl2 radical plasma due to the difference in activation energy between the UV-exposed and non-UV-exposed films. It is believed that dry development using Cl2 radicals will be one of the most important process techniques for next-generation patterning to remove problems such as pattern leaning, line edge roughness, residue, etc., caused by wet development.

Breaking the strength-ductility trade-off in austenitic stainless steel at cryogenic temperatures: Mechanistic insights

At cryogenic temperatures, 316L austenitic stainless steel (ASS) exhibits remarkable strength while retaining high ductility, defying the conventional stress-strain trade-off. Despite extensive studies documenting the cryo-tensile properties of ASSs, the underlying mechanisms behind this phenomenon remain largely unexplored. This study systematically re-examines the tensile properties of 316L stainless steel and the associated mechanisms across a range of low temperatures (293 K, 223 K, 123 K, and 77 K). The reasons for the superior stress-strain balance (∼80 % GPa) are discussed using results from electron backscatter diffraction (EBSD) microstructure characteristics. The results undoubtedly suggest that the transformation mechanisms, specifically the shift from deformation twinning to martensitic transformation (γ → ε → α′), play a crucial role in enhancing elongation at cryogenic temperatures. At these temperatures, the Gibbs free energy difference between ε-martensite and γ-austenite approaches zero, resulting in slow martensite growth. The stress-strain curves at low temperatures satisfy the Considère criterion, indicating delayed necking under these conditions. This behavior is ascribed to the presence of various hierarchical microstructures, including ε, α′, γ-twins, ε-twins and their intersections, which act as sources of work hardening. This study provides new insights into deformation behavior of ASSs under cryogenic conditions.

Fabrication of a novel microflower BiOCl composite incorporated with rosemary powder for enhanced oxygen vacancies and visible-light photocatalytic efficiency

Incorporating metallic or nonmetallic compounds is a promising method for enhancing the oxygen vacancies (OVs), charge transport, and visible light absorption of a bismuth oxychloride (BiOCl) semiconductor. This research aims to improve the properties of BiOCl by incorporating rosemary powder (RPC). BiOCl photocatalysts with enhanced OVs were synthesized through the addition of 1–4 wt% of RPC using a one-pot solvothermal process. The addition of 3 % RPC resulted in the formation of very small particles on the BiOCl lamellar structures, which were aligned with the (002) plane of carbon quantum dots (CQDs). The uniformly distributed CQDs transformed the BiOCl microstructure from a two-dimensional lamellar structure to a three-dimensional floral structure, leading to an increased surface area and pore volume. The incorporation of RPC enhanced the visible light absorption capacity of BiOCl. The carbon atoms in RPC readily attach to oxygen atoms in the Bi-O bond, disrupting the Bi-O lattice bond and forming OVs. The addition of RPC contributed to a higher number of OVs, which impacted both the energy difference between the valence and conduction bands and their locations. This resulted in better charge transfer and enhanced active species formation. The 3 %-RPC-BOC photocatalyst had the highest efficiency, achieving a 98 % degradation of rhodamine B (RhB) and a 45 % removal of organic carbon within 48 min under visible light. This composite also had excellent stability and reusability, as its crystal structure remained unaltered even after conducting 7 cycles. The primary active species of 3 %-RPC-BOC system is the superoxide radical (·O2-), while the hydroxyl radical (·OH) and hole (h+) operate as minor active species. Additionally, the 3 %-RPC-BOC achieved a high tetracycline (TC) removal rate of 82.1 %, which is 2.21 times higher than that of pure BiOCl.

Understanding the Impact of Hydroxyls on Synthesizing the Bimetallic Alloy Pt3Co on Al2O3 for CO-PROX

The anchoring effect between surface hydroxyls (–OH) and metal species has been extensively utilized to enhance catalyst stability. Nevertheless, few studies have investigated the impact of alloying process involving different types of –OH species. In this research, we discovered that the formation of the alloy particles Pt3Co was significantly influenced by the presence of distinct –OH species on Al2O3. Intriguingly, those Pt3Co alloy particles exclusively formed on α-Al2O3 owing to the weak interaction between both Pt and Co species and the triply bridging hydroxyls (µ3-OH). In contrast, Pt and Co species were found to be separately dispersed on γ-Al2O3 because of the strong anchoring effect of terminal hydroxyls (µ1-OH), especially for Co atoms. Density functional theory (DFT) calculations highlighted the difference in adsorption energies of the two metals on different hydroxyl groups, providing a theoretical rationale for the influence of hydroxyl groups on alloy formation. The presence of Pt3Co alloy resulted in a fourfold increase in the specific catalytic rate of Pt3Co/α-Al2O3 in CO-PROX compared to Pt3Co/γ-Al2O3. Arguably for the first time, this study demonstrates the association between alloy formation and –OH groups, providing a unique perspective on the design of alloy catalysts.

Modulating the electronic structure of Ni and Co in core-shell structured catalysts to enhance the efficiency of reductive amination of pyruvic acid

A core-shell structured catalyst 3Ni-7Co@SiO2-0.2 was created to facilitate the reductive amination of pyruvic acid into alanine and the yield of alanine is up to 99 %. The SiO2 shell played a crucial role in spatial isolation effect, preventing the direct hydrogenation of pyruvic acid and improving the selectivity of alanine. By inter-doping Ni and Co, the electronic structure and properties are adjusted, the d-band center is reduced which is beneficial to the desorption of the product and the reaction barrier is reduced. Furthermore, it is proposed that catalysts exhibit better reductive amination reaction performance when there is a smaller difference in adsorption energy between NH3 and H2 atoms on the metal surface.

Metal-enhanced carbon-nitrogen material for selective detection of hazardous gases: Insights from interface electronic states

In this study, utilizing density functional theory, the C3N1 monolayer modified by Ir, Pd, Pt, and Rh atoms (Ir/Pd/Pt/Rh-C2N1) was chosen for selective adsorption of C2H2 amidst multiple gases (H2O, C2H2, and C4H10O2). According to the results of cohesive energy and ab initio molecular dynamics simulations, it is indicated that precious metal atoms can be stably anchored on the monolayer while enhancing the conductivity of the material The analysis of the electrostatic potential and work function determined the highly active sites and electron release capacity. In addition, the adsorption energy and distance disclosed the gas-solid interface structure of multiple gases on the Ir/Pd/Pt/Rh-C2N1 monolayer. Importantly, C2H2 exhibits strong responses to p-type semiconductor Pt-C2N1 and n-type semiconductor Ir-C2N1, respectively. Crystal Orbital Hamilton Population reveals the difference in adsorption energy due to modifications involving four precious metals. Interestingly, for the first time, the density of states calculation reveals that under the coexistence of multiple gases, the Pt/Ir-C2N1 monolayer effectively eliminates the interference of other gases and has a unique response only to C2H2. In real situations, with the basis of Gibbs free energy and Einstein's law of diffusion, it was determined that Pt-C2N1 and Ir-C2N1 showed excellent hydrophobicity, a wider temperature range, and a low diffusion activation energy barrier. In summary, Pt-C2N1 and Ir-C2N1 detect C2H2 without interference, maintaining fundamental principles, responsiveness, stability, and versatility unaffected by external factors.

Ion Transport at Polymer-Argyrodite Interfaces.

Solid-state electrolytes, particularly polymer/ceramic composite electrolytes, are emerging as promising candidates for lithium-ion batteries due to their high ionic conductivity and mechanical flexibility. The interfaces that arise between the inorganic and organic materials in these composites play a crucial role in ion transport mechanisms. While lithium ions are proposed to diffuse across or parallel to the interface, few studies have directly examined the quantitative impact of these pathways on ion transport and little is known about how they affect the overall conductivity. Here, we present an atomistic study of lithium-ion (Li+) transport across well-defined polymer-argyrodite interfaces. We present a force field for polymer-argyrodite interfacial systems, and we carry out molecular dynamics and enhanced sampling simulations of several composite systems, including poly(ethylene oxide) (PEO)/Li6PS5Cl, hydrogenated nitrile butadiene rubber (HNBR)/Li6PS5Cl, and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/Li6PS5Cl. For the materials considered here, Li-ion exhibits a preference for the ceramic material, as revealed by free energy differences for Li-ion between the inorganic and the organic polymer phase in excess of 13 kBT. The relative free energy profiles of Li-ion for different polymeric materials exhibit similar shapes, but their magnitude depends on the strength of interaction between the polymers and Li-ion: the greater the interaction between the polymer and Li-ions, the smaller the free energy difference between the inorganic and organic materials. The influence of the interface is felt over a range of approximately 1.5 nm, after which the behavior of Li-ion in the polymer is comparable to that in the bulk. Near the interface, Li-ion transport primarily occurs parallel to the interfacial plane, and ion mobility is considerably slower near the interface itself, consistent with the reduced segmental mobility of the polymer in the vicinity of the ceramic material. These findings provide insights into ionic complexation and transport mechanisms in composite systems, and will help improve design of improved solid electrolyte systems.

Average Carbohydrate and CaLoric Intake of Patients with Type-2 diabetes at a tertiary care hospital in Pakistan: ACCLIP study.

Type-2 Diabetes Mellitus (T2DM) is one of the most common chronic non-communicable diseases and a serious health issue worldwide because of its rising prevalence amongst the young adults. Dietary diversity, rapid economic development and sedentary lifestyle are amongst the common factors contributing for the rapid rise of diabetes. Our objective was to assess the average carbohydrate (CHO) and caloric consumption and its association with obesity and disease status in patients with Type-2 diabetic patients in an outpatient setting. This study was performed at an outpatient department (OPD), of Hayatabad Medical Complex, Peshawar. Patients with T2DM were interviewed who completed dietary assessment using 24 hours dietary recall method. A total of 150 patients with Type-2 diabetes were interviewed. The mean carbohydrate intake was 400.3±106 mg/day, out of which 43.3 % participant's had carbohydrate intake above recommendations. The mean energy intake for all participants was 2504.5±587.4 Kcal/day. Majority of the participants were overweight and obese with mean BMI of 28kg/m2 ± 4.4. There was no significant difference in energy and carbohydrate intake between male and female participants. Majority of Pakistani patients with Type-2 diabetes consume foods rich in carbohydrate as well as have high caloric value. These finding were more in patients with no formal education compared to those who were well educated with a degree.

Revealing the surface structure and morphology evolution of Co nanoparticle supported on ZrO2 surfaces

The optimization of structure-dependent activity of supported metal catalysts has driven the dynamic determination of the morphology of Co nanoparticles on ZrO2 using atomic-level simulations. Density functional theory (DFT) calculations combined with ab initio molecular dynamics (AIMD) simulations were used to investigate the surface structure, nucleation mechanism and morphology evolution of Con clusters supported on different ZrO2 facets. As the size of the Con (n = 1–5) cluster increases, the competition between Co-Co bonding and the interaction of Con clusters with the ZrO2 surface further promotes the nucleation of larger clusters. Co atoms prefer to nucleate into large clusters on both c-ZrO2(111) and t-ZrO2(101) surfaces, but this behavior is unfavorable on the m-ZrO2(-111) surface. The analysis of electric properties suggests that the types of hybrid orbitals and the number of electron transfer accounts for the difference in energies of Con clusters on ZrO2 surfaces. Further, the AIMD simulations verified the stable structure of small Co5 cluster obtained by DFT, and predicted the morphology of large Co13 clusters on ZrO2 surfaces under realistic reaction conditions, consistent with the experimental SAM images. Our work provides an intuitive understanding of structure and morphology evolution of catalysts for the targeted design of catalysts to achieve the desired activity and explore more reaction possibilities.

Concentration Scales and Solvation Thermodynamics: Some Theoretical and Experimental Observations Regarding Spontaneity and the Partition Ratio.

The solvation thermodynamics (ST) formalism proposed by A. Ben-Naim is a mathematically rigorous and physically grounded theory for describing properties related to solvation. It considers the solvation process as the transfer of a molecule ("solute") from a fixed position in the ideal gas phase to a fixed position within the solution. Thus, it removes any contribution to the solvation process that is not related to the interactions between this molecule and its environment in the solution. Because ST is based on statistical thermodynamics, the natural variable is number density, which leads to the amount (or "molar") concentration scale. However, this choice of concentration scale is not unique in classical thermodynamics and the solvation properties can be different for commonly used concentration scales. We proposed and performed experiments with diethylamine in a water/hexadecane heterogeneous mixture to confront the predictions of the ST, based on the amount (or "molar") concentration scale, and the Fowler-Guggenheim formalism, based on the mole fraction scale. By means of simple acid-base titration and 1H NMR measurements, it was established that the predictions of differences in the solvation Gibbs energy and the partition ratio (or "partition coefficient") of diethylamine between water and hexadecane are consistent with the ST formalism. Additionally, with current literature data, we have shown additional experimental support for the ST. However, due to the arbitrariness of the relative amount of solvents in the partition ratio, the choice of a single concentration scale within the classical thermodynamics is still not possible.

Enhancing the reliability of InP-based QD color conversion layer through a uniform organic encapsulation layer via inkjet printing

Quantum dot (QD) as a color conversion layer (CCL) is gaining increasing attention for use in next generation displays. However, QD CCL, especially those based on indium phosphide (InP) materials, are vulnerable to oxygen and moisture. Accordingly, even in CCL technology, encapsulation is essential to mitigate performance reduction due to the degradation of color conversion efficiency (CCE). Herein, we employed only acrylic-based resin to produce a uniform encapsulation layer on a CCL, enhancing the CCE reliability of the QD CCL under ambient conditions. To print a uniform encapsulation layer, we confirmed the significance of the minimized surface energy differences on glass, bank, and QD film through O2 plasma treatment. We also investigated coating characteristics through adjustment of the drop spacing to analyze the reliability of the CCL. Compared to the CCL without an encapsulation layer, the CCE only showed a decrease of 1.96 % at green and 3.6 % at red light, after 168 h. The T95 (time to 95 % of the initial luminance) was improved from 5.25 h to 75.02 h by applying the encapsulation layer. As a result, we enhanced the stability of the InP-based QD CCL by printing only an organic encapsulation layer using the inkjet printing process.

Development of food for special dietary uses of diabetes based on oyster mushroom and brown rice

Diabetes patients often struggle to meet their energy requirements, prompting the suggestion of utilizing Food for Special Dietary Uses (FSDU). Previous research has shown the efficacy of oyster mushrooms’ B-glucan in controlling hyperglycemia and insulin resistance. Brown rice, high in magnesium and fiber with a low glycemic index, is known to lower blood glucose levels. Utilizing both ingredients in FSDU may provide products with recommended energy value, nutrient ingredients, and glycemic index. This study aimed to measure the energy, protein, fat, carbohydrate, fiber, glucose, and glycemic index of four mixed formulations of oyster mushrooms and brown rice, along with a control.The study used a true experimental design with a completely randomized research design. The formulations included: P1=9% mixture of moringa and fish flour, P2=10% mixture of carrot and fish flour, F3=11% mixture of moringa and tempeh flour, and F4=12% tempeh flour. The total energy was measured using various methods: adiabatic oxygen bomb calorimeter for energy, Kjeldahl for protein, Soxhlet for fat, by-difference for carbohydrates, AOAC enzymatic-gravimetric for total dietary fiber, anthrone for total sugar, and blood glucose tests at 0, 15, 30, 45, 60, 90, and 120 minutes post-test-food ingestion for glycemic index measurements. Statistical analysis was performed using the One-Way ANOVA and Kruskal-Wallis tests.The research results indicate significant differences in energy, protein, fat, carbohydrates, total sugar, and fiber values among groups (p<0.01). The lowest glycemic index was found in P4 (44.32, medium category). Further analysis indicated that P4 had higher total energy and fat, but lower carbohydrates, total sugar, and glycemic index. According to the Multiple Attribute Zeleny Method, the P4 formula was the best formula for all parameters.The most effective formula, containing brown rice, oyster mushrooms, and tempeh flour (P4), could be a beneficial option for improving the health of individuals with diabetes in the community.

Energetics and Structural Transitions of Nonequivalent Polytypes for FCC and HCP Metals

AbstractAlthough metal nanomaterials with unconventional phases have attracted extensive attention, the lack of information on the characteristics of metal polytypes hinders the development of related research. In this work, the energetics of nonequivalent polytypes for bulk face‐centered cubic (Li, Al, Ca, Cu, Sr, Rh, Pd, Ag, Ir, Pt, Au, and Pb) and hexagonal close‐packed metals (Be, Na, Mg, Sc, Ti, Zn, Cd, Y, Zr, Tc, Ru, Hf, Re, Os, and Tl) is systematically reported. For each metal, the structural properties and energies for its polytypes with up to the periodic stacking length of L = 10 is obtained by DFT calculation. The variation tendency of the energy differences between 3C and 2H polytypes is summarized in the Periodic Table of Elements. Generally, the ratio c/(La) increases when metal crystals except Ir, Rh, Zn, and Cd leave away from their ground‐state structure. It is found that the energy difference between polytypes originates from various interactions between the two types of atomic layers: the k layer and the h layer. The work is helpful to understand not only the structural transitions in bulk metals, such as Li, Na, Sr, Ti, Al, Pb, Y, Re, and Tl, but also the evolutions of Au nanomaterials.

Single-crystal growth, crystal structure, and molecular dynamics of organic–inorganic [NH3(CH2)2NH3]CuBr4

As part of obtaining excellent properties that can be used as lead-free hybrid solar cells, the crystal growth, crystal structure, phase transition temperature, and thermal properties for [NH3(CH2)2NH3]CuBr4 were discussed. The crystal structure at 300 K was determined to be monoclinic by single-crystal X-ray diffraction (XRD) analysis. The phase transition temperatures were determined to be 447 and 473 K, and the results were consistent with the powder XRD patterns. Thermogravimetric analysis revealed thermal stability up to ~ 460 K. The continuous changes in the 1H and 13C chemical shifts and 14N static resonance frequency with increasing temperature are related to variations in the local environment and coordination geometry. The significant differences in activation energies obtained from the 1H and 13C spin–lattice relaxation times (t1ρ) at low and high temperatures were discussed. The activation energy results suggested that the energy barrier at low temperatures was related to the reorientation of the NH3 and CH2 groups around the three-fold symmetry axis, and the energy barrier at high temperatures was related to the reorientation of the [NH3(CH2)2NH3] cation. These physical properties will be provide important insights or potential applications of this crystal.Please check and confirm that the corresponding author and their respective corresponding affiliation have been correctly identified and amend if necessary.OK !

Structures and stabilities Ru-doped Agn (n = 1–13) clusters: Ag10Ru a 18-ve cluster superatom

The geometrical and stability properties of Ru-doped silver clusters (AgnRu with n = 1–13) are investigated by density functional theory (DFT) calculations. The results show that the Ru dopant adopts central positions in the lowest-energy structures of AgnRu clusters. The most stable structures found are planar and curved for n = 3–6, while for n = 6 onward the structures follow a pentagonal growth pattern. Interestingly for n = 10, we found a cage structure with fulfills the 18 electron rule. The relative stability of the clusters is further evaluated through energetic parameters such as ionization energy, electron affinity, second order energy difference and HOMO–LUMO gap. The results show that the most stable structures in this series are Ag3Ru, Ag6Ru and Ag10Ru, as supported by electronic structure analyses. The plausible formation of the Ag10Ru cluster as a superatomic species is rationalized with 1.64 eV of HOMO–LUMO gap and 6.23 eV of adiabatic ionization energy.

The electric double layer structure and interface energy of uranium electrode in molten LiCl-KCl-UCl3 mixture: A molecular dynamics simulation study

The electric double layer structure and interface energy of uranium electrode in molten LiCl-KCl-UCl3 mixture, as well as the surface energies of metallic uranium and molten salts, were investigated using molecular dynamics simulations. The surface energies were calculated, respectively, from the pressure tensor and the energy difference for molten salt and uranium, and interface energy was evaluated from the Gibbs free energy difference between systems with and without interface. The surface energies of molten alkali halides are between 76.4 and 201.8 mJ·m−2 and decrease with the increase of radius of the halide anion or the alkali cation for molten salt with the same alkali cation or the same halide anion. The surface energy of uranium depends on the allotrope morphology and crystal facet, and the surface energies of α-U, β-U, and γ-U are 2.36, 1.45, and 1.69 J·m−2 in average for the seven low index crystal facets. The interface energy of uranium and molten LiCl-KCl-UCl3 mixture is about 2.71 J·m−2 and increases with the increase of charge density on the uranium slabs. The molten LiCl-KCl-UCl3 mixture in anodic zone has higher coordination number than that in cathodic zone but similar coordination distance.