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Reaction rate theory has been at the center of physical chemistry for well over one hundred years. The evolution of the theory is not only of historical interest. Reliable and accurate computation of reaction rates remains a challenge to this very day, especially in view of the development of quantum chemistry methods, which predict the relevant force fields. It is still not possible to compute the numerically exact rate on the fly when the system has more than at most a few dozen anharmonic degrees of freedom, so one must consider various approximate methods, not only from the practical point of view of constructing numerical algorithms but also on conceptual and formal levels. In this Perspective, I present some of the recent analytical results concerning leading order terms in an ℏ2m series expansion of the exact rate and their implications on various approximate theories. A second aspect has to do with the crossover temperature between tunneling and thermal activation. Using a uniform semiclassical transmission probability rather than the "primitive" semiclassical theory leads to the conclusion that there is no divergence problem associated with a "crossover temperature." If one defines a semiclassical crossover temperature as the point at which the tunneling energy of the instanton equals the barrier height, then it is a factor of two higher than its previous estimate based on the "primitive" semiclassical approximation. In the low temperature tunneling regime, the uniform semiclassical theory as well as the "primitive" semiclassical theory were based on the classical Euclidean action of a periodic orbit on the inverted potential. The uniform semiclassical theory wrongly predicts that the "half-point," which is the energy at which the transmission probability equals 1/2, for any barrier potential, is always the barrier energy. We describe here how augmenting the Euclidean action with constant terms of order ℏ2 can significantly improve the accuracy of the semiclassical theory and correct this deficiency. This also leads to a deep connection with and improvement of vibrational perturbation theory. The uniform semiclassical theory also enables an extension of the quantum version of Kramers' turnover theory to temperatures below the "crossover temperature." The implications of these recent advances on various approximate methods used to date are discussed at length, leading to the conclusion that reaction rate theory will continue to challenge us both on conceptual and practical levels for years to come. [ABSTRACT FROM AUTHOR]

Despite the wide existence of vesicles in living cells as well as their important applications like drug delivery, the underlying mechanism of vesicle fusion/fission remains under debate. Classical models cannot fully explain recent observations in experiments and simulations. Here, we develop a constrained self-consistent field theory that allows tracking the shape evolution and free energy as a function of center-of-mass separation distance. Fusion and fission are described in a unified framework. Both the kinetic pathway and the mechanical response can be simultaneously captured. By taking vesicles formed by polyelectrolytes as a model system, we predict discontinuous transitions between the three morphologies: parent vesicle with a single cavity, hemifission/hemifusion, and two separated child vesicles, as a result of breaking topological isomorphism. With the increase in inter-vesicle repulsion, we observe a great reduction in the cleavage energy, indicating that vesicle fission can be achieved without hemifission, in good agreement with simulation results. The force–extension relationship elucidates typical plasticity for separating two vesicles. The super extensibility in the mechanical response of vesicle is in stark contrast to soft particles with other morphologies, such as cylinder and sphere. Our work elucidates the fundamental physical chemistry based on intrinsic topological features of vesicle fusion/fission, which provides insights into various phenomena observed in experiments and simulations. [ABSTRACT FROM AUTHOR]

The on-demand assembly of 2D heterostructures has brought about both novel interfacial physical chemistry and optoelectronic applications; however, existing studies rarely focus on the complementary part—the 2D cavity, which is a new-born area with unprecedented opportunities. In this study, we have investigated the electric field inside a spacer-free 2D cavity consisting of a monolayer semiconductor and a gold film substrate. We have directly captured the built-in electric field crossing a blinking 2D cavity using a Kelvin probe force microscopy–Raman system. The simultaneously recorded morphology (M), electric field (E), and optical spectroscopy (O) mapping profile unambiguously reveals dynamical fluctuations of the interfacial electric field under a constant cavity height. Moreover, we have also prepared non-blinking 2D cavities and analyzed the gap-dependent electric field evolution with a gradual heating procedure, which further enhances the maximum electric field exceeding 109 V/m. Our work has revealed substantial insights into the built-in electric field within a 2D cavity, which will benefit adventures in electric-field-dependent interfacial sciences and future applications of 2D chemical nanoreactors. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the effectiveness of coating of abutments with antimicrobial agents and their influence on the physicochemical and biologic properties of the coated materials. Materials and Methods: This work was registered in Open Science Framework (osf.io/6tkcp) and followed the PRISMA protocols. A search of two independent reviewers of articles published up to October 29, 2021, was performed in the Embase, PubMed, Science Direct, and Scopus databases. Results: The databases found a total of 1,474 references. After excluding the duplicates, 1,050 remained. After reading the titles and abstracts and applying the inclusion criteria, 13 articles remained and were read in full. A total of 8 articles were included in this systematic review. Different antimicrobial agents have been used to coat abutments, including graphene oxide, polydopamine, titanium and zirconium nitride, lactoferrin, tetracycline, silver, and doxycycline with varied release times. Titanium-coated silver showed a better antimicrobial agent release time of up to 28 days. Chemical analysis confirmed the presence of antimicrobials on the surface after coating. Different pathogenic microorganisms, such as Streptococcus sanguinis, Streptococcus oralis, and Staphylococcus aureus, were inhibited when in contact with the coated surface. Conclusions: This review showed that there is still no consensus on which is the better antimicrobial agent and which coated materials have the better performance. However, the association of surface coating of abutments with antimicrobials is feasible and can benefit many patients, which can support their clinical use to favor the healing process and prevent infections that can lead to treatment failure with dental implants. [ABSTRACT FROM AUTHOR]

The solvent effects on the linear and second-order nonlinear optical properties of an aminonaphtylethenylpyridinium (ANEP) dye are investigated by combining experimental and theoretical chemistry methods. On the one hand, deep near infrared (NIR) hyper-Rayleigh scattering (HRS) measurements (1840–1950 nm) are performed on solutions of di-8-ANEPPS in deuterated chloroform, dimethylformamide, and dimethylsulfoxide to determine their first hyperpolarizablity (βHRS). For the first time, these HRS experiments are carried out in the picosecond regime in the deep NIR with very moderate (≤3 mW) average input power, providing a good signal-to-noise ratio and avoiding solvent thermal effects. Moreover, the frequency dispersion of βHRS is investigated for Disperse Red 1 (DR1), a dye commonly used as HRS external reference. On the other hand, these are compared with computational chemistry results obtained by using a sequential molecular dynamics (MD) then quantum mechanics (QM) approach. The MD method allows accounting for the dynamical nature of the molecular structures. Then, the QM part is based on TDDFT/M06-2X/6-311+G* calculations using solvation models ranging from continuum to discrete ones. Measurements report a decrease of the βHRS of di-8-ANEPPS in more polar solvents and these effects are reproduced by the different solvation models. For di-8-ANEPPS and DR1, comparisons show that the use of a hybrid solvation model, combining the description of the solvent molecules around the probe by point charges with a continuum model, already achieves quasi quantitative agreement with experiment. These results are further improved by using a polarizable embedding that includes the atomic polarizabilities in the solvent description. [ABSTRACT FROM AUTHOR]

Spherical harmonics provide a smooth, orthogonal, and symmetry-adapted basis to expand functions on a sphere, and they are used routinely in physical and theoretical chemistry as well as in different fields of science and technology, from geology and atmospheric sciences to signal processing and computer graphics. More recently, they have become a key component of rotationally equivariant models in geometric machine learning, including applications to atomic-scale modeling of molecules and materials. We present an elegant and efficient algorithm for the evaluation of the real-valued spherical harmonics. Our construction features many of the desirable properties of existing schemes and allows us to compute Cartesian derivatives in a numerically stable and computationally efficient manner. To facilitate usage, we implement this algorithm in sphericart, a fast C++ library that also provides C bindings, a Python API, and a PyTorch implementation that includes a GPU kernel. [ABSTRACT FROM AUTHOR]

Approximate solutions to the ab initio electronic structure problem have been a focus of theoretical and computational chemistry research for much of the past century, with the goal of predicting relevant energy differences to within "chemical accuracy" (1 kcal/mol). For small organic molecules, or in general, for weakly correlated main group chemistry, a hierarchy of single-reference wave function methods has been rigorously established, spanning perturbation theory and the coupled cluster (CC) formalism. For these systems, CC with singles, doubles, and perturbative triples is known to achieve chemical accuracy, albeit at O (N7) computational cost. In addition, a hierarchy of density functional approximations of increasing formal sophistication, known as Jacob's ladder, has been shown to systematically reduce average errors over large datasets representing weakly correlated chemistry. However, the accuracy of such computational models is less clear in the increasingly important frontiers of chemical space including transition metals and f-block compounds, in which strong correlation can play an important role in reactivity. A stochastic method, phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC), has been shown to be capable of producing chemically accurate predictions even for challenging molecular systems beyond the main group, with relatively low O (N3 − N4) cost and near-perfect parallel efficiency. Herein, we present our perspectives on the past, present, and future of the ph-AFQMC method. We focus on its potential in transition metal quantum chemistry to be a highly accurate, systematically improvable method that can reliably probe strongly correlated systems in biology and chemical catalysis and provide reference thermochemical values (for future development of density functionals or interatomic potentials) when experiments are either noisy or absent. Finally, we discuss the present limitations of the method and where we expect near-term development to be most fruitful. [ABSTRACT FROM AUTHOR]

In computational and theoretical chemistry, the eccentricity matrix of graph has widely applications due to its effect of eccentricity in molecular graph. Since a molecular structure is modeled by hypergraph which has a higher accuracy than by graph, it is also interesting to study eccentricity matrix of hypergraph. The eccentricity spectral radius of H is the spectral radius of its eccentricity matrix. In this paper, some properties on eccentricity spectral radius of hypergraphs are obtained and some extremal structure of hypertrees are characterized. [ABSTRACT FROM AUTHOR]

[Display omitted] Surfactants are inexpensive chemicals with promising applications in virus inactivation, particularly for enveloped viruses. Yet, the detailed mechanisms by which surfactants deactivate coronaviruses remain underexplored. This study delves into the virucidal mechanisms of various surfactants on Feline Coronavirus (FCoV) and their potential applications against more pathogenic coronaviruses. By integrating virucidal activity assays with fluorescence spectroscopy, dynamic light scattering and laser Doppler electrophoresis, alongside liposome permeability experiments, we have analyzed the effects of non-ionic and ionic surfactants on viral activity. The non-ionic surfactant octaethylene glycol monodecyl ether (C 10 EO 8) inactivates the virus by disrupting the lipid envelope, whereas ionic surfactants like Sodium Dodecyl Sulfate and Cetylpyridinium Chloride predominantly affect the spike proteins, with their impact on the viral membrane being hampered by kinetic and thermodynamic constraints. FCoV served as a safe model for studying virucidal activity, offering a faster alternative to traditional virucidal assays. The study demonstrates that physicochemical techniques can expedite the screening of virucidal compounds, contributing to the design of effective disinfectant formulations. Our results not only highlight the critical role of surfactant-virus interactions but also contribute to strategic advancements in public health measures for future pandemic containment and the ongoing challenge of antimicrobial resistance. [ABSTRACT FROM AUTHOR]

The various mechanisms of primary antioxidant action of a series of 2‐Methoxyphenols are investigated in the present work. The electronic properties have just been studied in a joint article, so that we focus here on Hydrogen Atom Transfer (HAT), Single Electron Transfer–Proton Transfer (SET–PT) and Sequential Proton‐Loss Electron‐Transfer (SPLET) mechanisms. The two computational approaches used in the previous study of the structure and reactivity of these compounds [Computational and Theoretical Chemistry 1229 (2023) 114287] provide identical mechanisms trends in gas phase. In gas media, hydrogen atom transfer (HAT) is more favored. On the contrary, the solvent polarity has a significant effect on the mechanism of the antioxidant activity, since the polarity of the solvent increases the contribution of the SPLET mechanism. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to identify a rapid, sensitive, and non-destructive auxiliary approach for postmortem diagnosis of SCD, addressing the challenges faced in forensic practice. Methods: ATR-FTIR spectroscopy was employed to collect spectral features of blood samples from different cases, combined with pathological changes. Mixed datasets were analyzed using ANN, KNN, RF, and SVM algorithms. Evaluation metrics such as accuracy, precision, recall, F1-score and confusion matrix were used to select the optimal algorithm and construct the postmortem diagnosis model for SCD. Results: A total of 77 cases were collected, including 43 cases in the SCD group and 34 cases in the non-SCD group. A total of 693 spectrogram were obtained. Compared to other algorithms, the SVM algorithm demonstrated the highest accuracy, reaching 95.83% based on spectral biomarkers. Furthermore, by combing spectral biomarkers with age, gender, and cardiac histopathological changes, the accuracy of the SVM model could get 100%. Conclusion: Integrating artificial intelligence technology, pathology, and physical chemistry analysis of blood components can serve as an effective auxiliary method for postmortem diagnosis of SCD. [ABSTRACT FROM AUTHOR]

Objective. Matrix metalloproteinase-2 (MMP2) overexpression has been considered as a hallmark of tumor aggressiveness. The significant roles of MMP2 in other human disorders, such as cardiovascular diseases and dental caries, have also been demonstrated. Herein, we used in silico approaches to evaluate the binding affinity of selected cinnamic acids to the MMP2 catalytic domain. The obtained findings were subsequently juxtaposed with those attributed to oleandrin, utilized as a reference pharmaceutical agent. Methods. This research employed the AutoDock software to assess the affinity of 19 herbal compounds derived from cinnamic acid to the catalytic cleft of MMP2. The ligands attaining the most negative scores, as determined by the Gibbs free binding energy assessments, were accorded the highest rankings. The interactions between the MMP2 and cinnamic acids ranked highest were elucidated using the Discovery Studio Visualizer tool. Molecular dynamics simulations were performed to investigate the structural stability of MMP2 backbone atoms when forming complexes with both the top-ranked inhibitor from this study and a standard drug. Results. Eight cinnamic acids were indicated with Δ G binding values less than −10 kcal/mol. Cynarin emerged as the most potent inhibitor of the enzyme, with the Δ G binding score and inhibition constant value of −15.19 kcal/mol and 7.29 pM, respectively. The MMP2 backbone atoms achieve stability around the 20 ns mark, displaying a root mean square deviation of approximately 3.2 Å when influenced by the top-ranked cinnamic acid, the standard drug, or in their free form. Conclusion. The inhibition of MMP2 by cinnamic acids, particularly cynarin, holds promise as a valuable therapeutic strategy for various human disorders, encompassing cancer, cardiovascular conditions, and dental caries. [ABSTRACT FROM AUTHOR]

Superconducting nanowire single-photon detectors (SNSPDs) in the mid-infrared (MIR) have the potential to open up numerous opportunities in fields such as exoplanet searches, direct dark matter detection, physical chemistry, and remote sensing. One challenge in pushing SNSPD sensitivity to the MIR is a decrease in the signal-to-noise ratio (SNR) of the readout signal, as the critical currents become increasingly smaller. We overcome this trade-off with a device architecture that employs impedance matching tapers and superconducting nanowire avalanche photodetectors to demonstrate increased SNR while maintaining saturated internal detection efficiency at 7.4 μm and approaching saturation at 10.6 μm. This work provides a platform for pushing SNSPD sensitivity to longer wavelengths while enabling the scalability to large arrays. [ABSTRACT FROM AUTHOR]

Chloronium, H2Cl+, is detected in astrophysical media. It is key chemical intermediate for understanding of the physical chemistry of chlorine species there. At present, we compute the collision rates for the rotational excitation and de-excitation of ortho- and para- H2Cl+ colliding with He for T  ≤ 150 K, relevant for the interstellar medium (ISM) conditions. Prior to that, we generated the 3D interaction potential of the weakly bound H2Cl+-He complex along the Jacobi coordinates. For electronic structure computations, we used a post-Hartree-Fock explicitly correlated method at the CCSD(T)-F12/aug-cc-pVTZ level. The analytical expansion of this potential was incorporated into close coupling computations of the cross-sections for the rotational excitation and de-excitation of ortho- and para- H2Cl+ colliding with He and for collision kinetic energies E k ≤ 1000 cm−1. The rates were obtained after averaging these cross-sections over a Maxwell–Boltzmann distribution of kinetic energies. Our data show that the ∆j=∆ka=∆kc=−1 de-excitation transitions exhibit the largest values, in particular those used to identify this cation in the surveys. Besides, our results should help for determining more accurate abundances of H2Cl+ in the ISM and thus better modelling the chlorine chemistry there. [ABSTRACT FROM AUTHOR]

The article focuses on supported atomically dispersed palladium (Pd) catalysis for direct alkoxylation and allylic alkylation, emphasizing the catalyst's efficiency and unique mechanism. It discusses the utilization of atomically dispersed Pd on titanium dioxide (TiO2) nanosheets for direct allylic alkylation from allylic alcohols, highlighting the role of hydrogen bonding at the organic-inorganic interface in facilitating the reaction.

Background Rosacea as a skin inflammatory disease may be triggered by some types of bacteria. Azelaic acid with antibacterial property can be used for treatment of skin conditions such as Rosacea. Objective In this study, we aim to prepare and evaluate the physicochemical properties and primary stability of 15% azelaic acid gel. Methods For the gel preparation, first, an aqueous solution containing ethylenediaminetetraacetic and benzoic acids was prepared. Then, a mixture of polysorbate 80 and triglyceride was added to the solution at 50°C. Then, lecithin, propylene glycol, and carbomer 940 P was added to the mixture, and stirred. After that, the gel was prepared. Then, 15 g of dissolved azelaic acid in propylene glycol was added to the gel. Finally, the formulation was homogenized for 15 min. Results On the day of production, all the formulations had a smooth appearance and the amount of azelaic acid was about 15%. In the preliminary stability study for 3 months, the amount of azelaic acid in the formulation 5 (F5), prepared using homogenizer, was more than 99% of drug content, without any significant difference with other formulations. The released drug from F5 was 30% in the first hour and 50% after 2 hours. Conclusion All prepared formulations have acceptable pH, viscosity, and drug content. In 3 months, the highest homogeneity of azelaic acid with the lowest standard deviation was seen in the F5 formulation, indicating the importance of using homogenizer in azelaic acid gel preparation. Also, the propylene glycol 18% w/w, in addition to having a co-solvent role, can increase the release of azelaic acid from the gel. [ABSTRACT FROM AUTHOR]

Laws of physical chemistry such as quantum mechanics, laws of chemical kinetics, and thermodynamics have been employed as a potential tool to generate some converging sum rules. Special emphasis has been given to Rayleigh–Schrödinger perturbation theory and the use of delta function potential to generate a number of sum rules. [ABSTRACT FROM AUTHOR]

A large number of medical experiments have confirmed that the features of drugs have a close correlation with their molecular structure. Drug properties can be obtained by studying the molecular structure of corresponding drugs. The calculation of the topological index of a drug structure enables scientists to have a better understanding of the physical chemistry and biological characteristics of drugs. In this paper, we obtain the exact formulas by virtue of the edge-partition method for m S O α (G) and K A (α , β) 1 (G). By the appropriate choice of parameters α and β , several new/old inequalities that reveal relationships between various topological indices are obtained. Our results remedy the lack of medicine experiments, thus providing a theoretical basis for pharmaceutical engineering. [ABSTRACT FROM AUTHOR]

The organic anion transporter 3 (OAT3), an important renal uptake transporter, is associated with drug-induced acute kidney injury (AKI). Screening and identifying potent OAT3 inhibitors with little toxicity in natural products, especially flavonoids, in reducing OAT3-mediated AKI is of great value. The five strongest OAT3 inhibitors from the 97 flavonoids markedly decreased aristolochic acid I-induced cytotoxicity and alleviated methotrexate-induced nephrotoxicity. The pharmacophore model clarified hydrogen bond acceptors and hydrophobic groups are the critical pharmacophores. These findings would provide valuable information in predicting the potential risks of flavonoid-containing food/herb-drug interactions and optimizing flavonoid structure to alleviate OAT3-related AKI. [ABSTRACT FROM AUTHOR]

The topological properties of the networks can be described by the Laplacian spectra, but resolving the Laplacian spectra of networks poses difficulties. In this study, a novel approach for solving the Laplacian spectrum of weighted composite networks is presented. We first give the definitions of three weighted graph operations, namely, Cartesian product, corona, and join. Second, the Laplacian spectra of these composite networks are calculated. Finally, we use the obtained Laplacian spectrum to deduce some topological properties of the networks, such as network coherence, entire mean first-passage time, and Laplacian energy, which have several applications in physical chemistry. [ABSTRACT FROM AUTHOR]

This document discusses the application of photocatalysts in environmental chemistry, specifically in the removal of contaminants from wastewater and the production of renewable energy. The use of titanium dioxide (TiO2) as a photocatalyst is highlighted, along with its limitations such as high recombination rate and the need for UV radiation. The document presents various approaches to overcome these limitations, including doping TiO2 with different materials, coupling it with other semiconductors, and creating heterojunctions. The document also includes studies on the use of other photocatalysts such as ZnO, copper sulfides, and ilmenite. Additionally, it explores the use of photocatalysis for water disinfection and the inactivation of microorganisms. Overall, this Special Issue provides a comprehensive overview of the field of photocatalysis and the advanced techniques used to enhance catalyst efficiency. [Extracted from the article]

The dynamic behaviour of a chemical system made of two coupled reactions is compared with that of a mechanical system consisting of two oscillating bodies connected by springs. First, the principle of energy departure from equilibrium is employed to derive the motion equations of both systems. Subsequently, the relevant characteristic frequencies and the amplitude parameters are obtained and analysed in terms of "Normal Modes". The results show that systems belonging to different branches of science can be analysed using the same methodologies. To elucidate the application of Normal Modes to chemistry, the dynamic analysis of a system consisting of a proton transfer reaction coupled to a complex formation reaction is described in the Supporting Information: the procedure enables the evaluation of rate constants, equilibrium constants and reaction enthalpies of a reacting chemical system made of two coupled reactions. The method is then extended to a cycle of three reactions. [ABSTRACT FROM AUTHOR]

Context: The influence of external electric fields (EEFs) on chemical substances has always been a hot topic in the field of theoretical chemistry research. 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is an energetic material with excellent comprehensive properties and enormous potential for application. This article explores the molecular structure, electronic structure, energy change, frontier molecular orbitals (FMOs) and density of states (DOS), UV–Vis spectra, and infrared spectra of LLM-105 under various electric field conditions. The results indicate that negative EEF can improve the stability of LLM-105, reflected in the initiation of changes in bond length and HOMO-LOMO gap. EEF has a significant impact on the electronic structure of LLM-105. The polarization of the electronic structure brings about a change in total energy, which is reflected in the analysis of energy changes. In addition, the external electric field will cause the frequency of the infrared spectra and the UV–Vis spectra to have different degrees of blue shift. The results of the analysis are helpful to understand the changes of energetic materials under the applied electric field. Methods: Based on the density functional theory (DFT), the structural optimization and energy calculation were carried out by using B3LYP/6-311G(d, p) and B3LYP/def2-TZVPP methods, respectively. After optimization convergence, vibration analysis was performed without imaginary frequencies to obtain stable configurations. Then, the molecular structure, electronic structure, energy changes, molecular orbital and density of states, UV–Vis spectra, and infrared spectra were analyzed. [ABSTRACT FROM AUTHOR]

Context: The abilities of Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 as catalysts for N2-RR to create the NH3 are investigated by theoretical levels. The ∆Eadoption and ∆Eformation of Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 are investigated. The ∆Eadsorption of N2-RR intermediates and ΔGreaction of reaction steps of N2-RR on Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 are examined. In acceptable mechanisms, the *NN → *NNH step is potential limiting step and *NN → *NNH step in enzymatic mechanism is endothermic reaction. The ∆Greaction of *NHNH2 → *NH2NH2 step on Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 are -0.904, -0.928, -0.860, -0.882, -0.817 and -0.838 eV, respectively. The Co-Al18P18 and Ni-Al21N21 have the highest ∆Greaction values for reaction steps of N2-RR. Finally, it can be concluded that the Co-Al18P18, Ni-Al21N21, Fe-B24N24 and Mn-B27P2 have acceptable potential for N2-RR by acceptable pathways. Methods: The structures of Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 and N2-RR intermediates are optimized by PW91PW91/6-311+G (2d, 2p) and M06-2X/cc-pVQZ as theoretical levels in GAMESS software. The convergence for force set displacement of Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 and N2-RR intermediates are 1.5 × 105 Hartree/Bohr and 6.0 × 10-5 Angstrom. The Opt = Tight and MaxStep = 30 are considered to optimize Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 and N2-RR intermediates. The frequencies of Co-Al18P18, Ni-Al21N21, Fe-B24N24, Mn-B27P27, Ti-C60 and Cu-Si72 and N2-RR intermediates are calculated. [ABSTRACT FROM AUTHOR]

The ongoing global research and development efforts on perovskite solar cells (PSCs) have led the power conversion efficiency to a high record of 26.1%. The optimization of PSC processing methods, the development of new compositions, and the introduction of passivation strategies are key factors behind the meteoric rise in performance. In particular, defect passivation and mitigation of ion migration via molecular engineering of the interfaces have played a critical role in enhancing the photovoltaic performance and operational stability of PSCs. The key interface engineering strategies enabling highly stable and efficient PSCs are focused here. The interface chemistry and the deleterious impact associated with it are discussed. The molecular design of effective modulators to mitigate the negative effects of perovskite interfaces is elaborated along with advanced characterization techniques to probe the interfaces. The progress of interface modification by multiple strategies is presented, and different modulator designs that are proven to be effective in mitigating the negative effects of perovskite interfaces are highlighted. Moreover, the main properties of effective interface modification strategies are summarized, and general design principles are deduced for future applications. Here, important insights are provided into the fields of material chemistry, physical chemistry, and optoelectronics. [ABSTRACT FROM AUTHOR]

Oil-immersed transformers play a pivotal role owing to their environmentally friendly characteristics, compact footprint, and cost-effectiveness. Ensuring the online monitoring of oil-immersed transformers is a fundamental measure to ensure the secure and stable operation of modern power systems. In this paper, metal particle cluster-doped SnS is firstly used in the adsorption and sensing of decomposition components (CO, C2H2) under fault conditions in oil-immersed transformers. The study comprehensively analyzed band structure, differential charge density, density of states, and molecular orbital theory to unveil the adsorption and sensing mechanisms of target gases. The findings suggest that the modification of metal particle clusters can enhance the surface electronic properties of single-layer SnS. In the regions of metal particle clusters and the gas–surface reaction area, electronic activity is significantly heightened, primarily attributed to the contribution of d-orbital electrons of the metal cluster structures. The modified SnS exhibits adsorption capacity in the following order: Ru3-SnS > Mo3-SnS > Au3-SnS. Additionally, the modified material demonstrates increased competitiveness for C2H2, with adsorption types falling under physical chemistry adsorption. Different metal elements exert diverse effects on the electronic distribution of the entire system, providing a theoretical foundation for the preparation of corresponding sensors. The findings in this work offer numerical insights for the further preparation and development of SnS nanosensors, concurrently shedding light on the online monitoring of faults in oil-immersed transformers. [ABSTRACT FROM AUTHOR]

The article discusses the field of molecular simulation, which has seen rapid growth due to advancements in computer efficiency and simulation methods. Molecular simulation allows for the modeling of complex systems and the study of physical, chemical, and biochemical phenomena. The article highlights the importance of combining quantum mechanics and classical physics in simulation methods. It also mentions the use of molecular dynamics simulations in biochemistry and molecular biology, as well as their applications in medicine, pharmacy, and food science. The article concludes by discussing the future potential of molecular simulations, including their use in nanotechnology and the potential impact of artificial intelligence. The special issue presented in the article focuses on the modeling of processes at interfaces, the determination of properties of modern materials, and the investigation of complex macromolecules. [Extracted from the article]

We describe the components and implementation of an activity for multivariable calculus featuring applications to the field of chemistry. This activity focuses on the isobaric thermal expansion coefficient found using partial differentiation of the volume of an ideal gas with respect to temperature as pressure is held constant. Broader goals of this activity include enhancing calculus conceptual understanding, encouraging further interdisciplinary study and exploration, and cultivating mathematicians and scientists with broader and deeper backgrounds. [ABSTRACT FROM AUTHOR]

Thermodynamics is one of the most fascinating parts of physical chemistry, involved in different natural phenomena. In particular, the spontaneity or non-spontaneity of a chemical reaction is directly linked to fundamental thermodynamic parameters such as the Gibbs free energy change. Commonly this can be easily correlated with the electric work produced or required during an electrochemical reaction. In this context, the direct visualization of the electromotive force facilitates the student's understanding of the fundamental concepts behind the spontaneity of coupled reactions. Herein, we take advantage of the concepts of endogenous and exogenous bipolar electrochemistry to develop an easy and straightforward approach for the introduction of the thermodynamic concept of spontaneity to undergraduate students. In such a wireless electrochemical approach, the chemical information of two coupled reactions is encoded by the light emission of a light-emitting diode employed as bipolar electrode. This results in a direct optical readout of thermodynamic information of the involved redox reactions. [ABSTRACT FROM AUTHOR]

This paper presents a handful of electrochemical experiments related to one single system that opens up the way to teach a bunch of topics related to physical and inorganic chemistry, hence serving experience-oriented education of otherwise hard-to-understand fields. The key idea is the electrodeposition of metals from the same bath containing Cu2+ and Ni2+ ions onto electrodes that differ from each other either in size or position within the electrochemical cell. With the proper optimization of the current densities, pure Cu and a Ni-rich coating with shiny silver colour can be obtained on electrodes of large and small surface area, respectively. It will be explained in detail how to drive the discussion on the experiment so that the audience learns which processes can be treated as parallel ones (i.e. the deposition of two metals, Cu and Ni), the mass transport taking place in serial with the electrochemical reaction, and the occurrence of the mass transport limitation in an electrode process. Didactic aspects of the experiment are presented for both high school and undergraduate levels, and control experiments are also suggested to verify the conclusions achieved. Collateral topics of chemistry and materials science that can be brought up in connection with the experiment are also enumerated. [ABSTRACT FROM AUTHOR]

This editorial discusses the importance of education in the field of electrochemistry, highlighting its value in developing science, cultivating virtuous habits, enriching culture, and providing pleasure. The author emphasizes the Humboldtian ideal of the unity of research and education and expresses concern about the prioritization of market-orientation in universities. The editorial also discusses the challenges faced by researchers, such as administrative duties and writing research proposals, and the potential consequences for scientific and teaching activities. The author acknowledges the positive contributions of scientists sharing their experiences in education and expresses optimism about the future, while also discussing the use of artificial intelligence and machine learning in education. They emphasize the importance of coordinating different educational activities, using the internet in education, and maintaining the use of native languages in teaching. The author believes that textbooks will continue to play an important role in education but should be supplemented with modern and peer-reviewed texts. They also highlight the role of students in the teaching process and express hope that the contributions in this special issue will contribute to the improvement of teaching electrochemistry. [Extracted from the article]

SUMMARY OF COVERED AREAS Several articles in this special topics issue focus on the location of solid-fluid phase equilibria lines, using either simulation,[[17], [19], [21], [23]] theoretical,[21] or experimental methods.[24] Knowledge of coexistence lines is obviously interesting on its own right, but several articles highlight other reasons why precise knowledge of phase equilibria is relevant. Obtaining a deep knowledge of the behavior of condensed phases (solids, liquids, and amorphous) is a great challenge. This challenge is compounded in studies in which two or more phases need to be described simultaneously, for example, in the characterization of solid-liquid interfaces or the prediction of solid-liquid phase equilibrium. [Extracted from the article]

Development of the electronic kinetic-energy density functional is a subject of major interest in theoretical physics and chemistry. In this work, the nonlocal kinetic-energy functional is developed in terms of the response function for the molecular system to realize the orbital free density-functional theory (OF-DFT) to be utilized in the hybrid QM/MM (quantum mechanical/molecular mechanical) method. The present approach shows a clear contrast to the previous functionals where the homogeneous electron gas serves as a reference to build the response function. As a benchmark test, we apply the method to a QM water molecule in a dimer system and that embedded in a condensed environment to make comparisons with the results given by the QM/MM calculations employing the Kohn–Sham DFT. It was found that the energetics and the polarization density of the QM solute under the influence of the MM environment can be adequately reproduced with our approach. This work suggests the potential ability of the kinetic-energy functional based on the response functions for the molecular reference systems. [ABSTRACT FROM AUTHOR]

The use of fully or partially absorbing boundary conditions for diffusion-based problems has become paradigmatic in physical chemistry and biochemistry to describe reactions occurring in solutions or in living media. However, as chemical states may indeed disappear, particles cannot, unless such degradation happens physically and should, thus, be accounted for explicitly. Here, we introduce a simple, yet general idea that allows one to derive the appropriate boundary conditions self-consistently from the chemical reaction scheme and the geometry of the physical reaction boundaries. As an illustration, we consider two paradigmatic examples, where the known results are recovered by taking specific physical limits. More generally, we demonstrate that our mathematical analysis delivers physical insight that cannot be accessed through standard treatments. [ABSTRACT FROM AUTHOR]

In recent years there has been a renewed interest in benchtop NMR. Given their lower cost of ownership, smaller footprint, and ease of use, they are especially suited as an educational tool. Here, a new experiment targeted at upper‐year undergraduates and first‐year graduate students follows the conversion of D‐glucose into ethanol at low‐field. First, high and low‐field data on D‐glucose are compared and students learn both the Hz and ppm scales and how J‐coupling is field‐independent. The students then acquire their own quantitative NMR datasets and perform the quantification using an Electronic Reference To Access In Vivo Concentration (ERETIC) technique. To our knowledge ERETIC is not currently taught at the undergraduate level, but has an advantage in that internal standards are not required; ideal for following processes or with future use in flow‐based benchtop monitoring. Using this quantitative data, students can relate a simple chemical process (fermentation) back to more complex topics such as reaction kinetics, bridging the gaps between analytical and physical chemistry. When asked to reflect on the experiment, students had an overwhelmingly positive experience, citing agreement with learning objectives, ease of understanding the protocol, and enjoyment. Each of the respondents recommended this experiment as a learning tool for others. This experiment has been outlined for other instructors to utilize in their own courses across institutions, with the hope that a continued expansion of low‐field NMR will increase accessibility and learning opportunities at the undergraduate level. [ABSTRACT FROM AUTHOR]

This review reports the recent progress on ATR-far ultraviolet (FUV) spectroscopy in the condensed phase. ATR-FUV spectroscopy for liquids and solids enables one to explore various topics in physical chemistry, analytical chemistry, nanoscience and technology, materials science, electrochemistry, and organic chemistry. In this review, we put particular emphasis on the three major topics: (1) studies on electronic transitions and structures of various molecules, which one cannot investigate via ordinary UV spectroscopy. The combined use of ATR-FUV spectroscopy and quantum chemical calculations allows for the investigation of various electronic transitions, including σ, n-Rydberg transitions. ATR-FUV spectroscopy may open a new avenue for σ-chemistry. (2) ATR-FUV spectroscopy enables one to measure the first electronic transition of water at approximately 160 nm without peak saturation. Using this band, one can study the electronic structure of water, aqueous solutions, and adsorbed water. (3) ATR-FUV spectroscopy has its own advantages of the ATR method as a surface analysis method. ATR-FUV spectroscopy is a powerful technique for exploring a variety of top surface phenomena (∼50 nm) in adsorbed water, polymers, graphene, organic materials, ionic liquids, and so on. This review briefly describes the principles, characteristics, and instrumentation of ATR-FUV spectroscopy. Next, a detailed description about quantum chemical calculation methods for FUV and UV regions is given. The recent application of ATR-FUV-UV spectroscopy studies on electronic transitions from σ orbitals in various saturated molecules is introduced first, followed by a discussion on the applications of ATR-FUV spectroscopy to studies on water, aqueous solutions, and adsorbed water. Applications of ATR-FUV spectroscopy in the analysis of other materials such as polymers, ionic liquids, inorganic semiconductors, graphene, and carbon nanocomposites are elucidated. In addition, ATR-FUV-UV-vis spectroscopy focusing on electrochemical interfaces is outlined. Finally, FUV-UV-surface plasmon resonance studies are discussed. [ABSTRACT FROM AUTHOR]

This article, published in the journal Global Change Biology, discusses the role of energy in microbial processes in soil. The authors address questions raised by another study and highlight the importance of energy for microorganisms in soil. They emphasize that microorganisms primarily use organic carbon as an energy source rather than for biomass production. The article also discusses the concept of microbial energy use efficiency (EUE) and how it can be assessed using the enthalpy of organic compounds. The authors conclude that understanding the energy content of substrates can help calculate the enthalpy changes in soil systems. [Extracted from the article]

Context: The present work encompasses the theoretical investigation of 14 benzimidazole-based (seven vinyl fused monomeric benzimidazole (VFMBI) and seven vinyl fused oligomeric benzimidazole (VFOBI)) derivatives using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) techniques. The effects of electron donor and acceptor groups on the electronic structure such as HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies, HOMO-LUMO energy gap, ionization potentials (IPs), electron affinities (EAs), internal reorganization energies of holes and electrons (λh/e), and excited state properties have been explored in the present work. In addition, natural bond orbital (NBO) analysis of these compounds has been investigated to reveal the typical stabilization interactions in these molecules. Hence, the aim of the present work is to explore the electronic structures and optoelectronic properties of the title molecules on the basis of the DFT quantum chemical calculations and to make an idea on the parameters influencing the optoelectronic efficiency toward a better understanding of the structure-property relationships. Moreover, the calculated results reveal the suitable optoelectronic properties of benzimidazole oligomer derivatives using theoretical techniques. Of the investigated molecules, 4_MABIMCY and 4_MABIOCY show potential optoelectronic properties and can be used as a potential charge transport material due to their narrow band gap, high hyperpolarizability, low ionization potential, and high electron affinity. The larger λab and λem values favor the system to be used as a potential optoelectronic material with better optical properties. Methods: All quantum chemical calculations were carried out using Gaussian09 theoretical chemistry code. Ground state calculations were made using the B3LYP/6-31+G(d,p) method. All excited state calculations had been computed using TDB3P86/6-311++(d,p). The initial structure for excited state calculations was optimized using the AM1 semi-empirical method. [ABSTRACT FROM AUTHOR]

This document provides a comprehensive overview of opal, an amorphous solid, discussing its composition, properties, and various types of opal textures. It highlights that opal does not contain cristobalite or tridymite domains, distinguishing it from other substances. The document also explores the presence of water in opals and concludes that opal-A represents a specific stage in the formation of opals. Additionally, the author questions the usefulness of opal phase transitions as stratigraphic markers in sedimentary basins. The document acknowledges the assistance of other researchers and is dedicated to the author's advisor. [Extracted from the article]

The article discusses the advanced characterization of materials in electronic devices using atom probe tomography (APT). APT, providing sub-nanometer 3D maps with high analytical sensitivity, is highlighted for its role in understanding failure modes influenced by material choice, processing methods, and service conditions. Topics include the evolution of APT, experimental overview, scope of material characterization, and examples of its applications in electronic devices.

Cyclopentane‐1,3‐diyl diradicals (DRs) provide excellent opportunities to study the properties of diradicals because their lifetimes can be significantly lengthened to up to milliseconds with the introduction of proper substituents. This study investigated the bonding characteristics of singlet and triplet DRs having C=O and p‐cyanophenyl groups (S‐DR3 and T‐DR3) by monitoring the photo‐induced formation of the diradicals from their precursor azo compounds using time‐resolved IR (TR‐IR) spectroscopy. Upon the formation of S‐DR3, a C=O stretching wavenumber was upshifted by 22 cm−1, whereas a C≡N stretching one was downshifted by 12 cm−1. The observed shifts indicate that the unpaired electrons increase and decrease the C=O and C≡N bond orders, respectively. The effects of the unpaired electrons in S‐DR3 were similar to those observed in our previous TR‐IR studies on a singlet cyclopentane‐1,3‐diyl diradical having C=O but no C≡N groups (S‐DR2) and on that having C≡N but no C=O groups (S‐DR1), respectively. Contrastingly, upon the formation of T‐DR3, the C=O wavenumber was downshifted by 16 cm−1, indicating that the unpaired electrons decrease the C=O bond order. More notably, no detectable shifts were observed in the C≡N stretching wavenumber. These observations are not clearly explained by a model suggested in the previous studies on S‐DRs. Here, we discuss and propose a more elaborated resonance hybrid of DRs that can explain the directions and relative magnitudes of the observed wavenumber shifts irrespective of spin multiplicities. We expect that the findings and suggestions presented here will stimulate research in both organic and theoretical chemistry. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Charge transport characterization of single‐molecule junctions is essential for the fundamental research of single‐molecule physical chemistry and the development towards single‐molecule electronic devices and circuits. Among the single‐molecule conductance characterization techniques, the single‐molecule break junction technique is widely used in tens of worldwide research laboratories which can generate a large amount of experimental data from thousands of individual measurement cycles. However, data interpretation is a challenging task for researchers with different research backgrounds, and the different data analysis approaches sometimes lead to the misunderstanding of the measurement data and even reproducibility issues of the measurement. It is thus a necessity to develop a user‐friendly all‐in‐one data analysis tool that automatizes the basic data analysis in a standard and widely accepted way. In this work, we present the XMe Code (Xiamen Molecular Electronics Code), an intelligent all‐in‐one data analysis tool for the comprehensive analysis of single‐molecule break junction data. XMe code provides end‐to‐end data analysis that takes in the original experimental data and returns electronic characteristics and even charge transport mechanisms. We believe that XMe Code will promote the transparency of the data analysis in single‐molecule electronics and the collaborations among scientists with different research backgrounds. [ABSTRACT FROM AUTHOR]

Optical tweezers (OT), or optical traps, are a device for manipulating microscopic objects through a focused laser beam. They are used in various fields of physical and biophysical chemistry to identify the interactions between individual molecules and measure single-molecule forces. In this work, we describe the development of a homemade optical tweezers device based on a cost-effective IR diode laser, the hardware, and, in particular, the software controlling it. It allows us to control the instrument, calibrate it, and record and process the measured data. It includes the user interface design, peripherals control, recording, A/D conversion of the detector signals, evaluation of the calibration constants, and visualization of the results. Particular stress is put on the signal filtration from noise, where several methods were tested. The calibration experiments indicate a good sensitivity of the instrument that is thus ready to be used for various single-molecule measurements. [ABSTRACT FROM AUTHOR]

Nanosheets with boron elements have excellent characteristics which makes the boron polymorphs unique and super hard. A boron α -icosahedral nanosheet in crystalline form has superconductivity and thermal electronic properties. In theoretical chemistry and QSPR/QSAR study, a topological descriptor is an important analytical tool. It helps to analyse the structure and its properties and also correlates the with numerical expressions. The valence-based M-polynomial provides quantitative measures of molecular properties based on their geometric, electrostatic, and quantum chemical characteristics. In this article, the QSPR/QSAR analysis is performed for this nanosheet and the analytical expressions are validated with original synthesized data, and received excellent correlation values of 0.9835 and 0.9932. The mathematical expression of the structure is analysed and the indices are compared graphically and numerically. [ABSTRACT FROM AUTHOR]

The rate coefficients of H + O 2 = O + OH (R1) were reevaluated using the reported shock tube experimental data from Ryu et al. (1995), Yuan et al. (1991), Masten et al. (1991) and Hong et al. (2011) based on our latest kinetic mechanism [Xueliang Yang et al., Journal of Physical Chemistry A, 2021, 125, 10223–10234]. The statistical analysis using weighted average and weighted least-square regression was performed by applying the updates on specific rates and corresponding uncertainties. The chain-termination reaction of H + O 2 (+ M) = HO 2 (+ M) (R2) was reevaluated as well. New rate formulae of R1 and R2 were derived and incorporated back into the mechanism. The validation demonstrates the updated mechanism has good performance against the measurements such as mass burning rate and ignition delay time at broad range of initial conditions. • The reaction rates of H + O 2 were reevaluated based on shock tube experiments. • Uncertainties of reaction rates were assessed for weighted statistical analysis. • The updated mechanism with reevaluated rates was validated against the measurements. [ABSTRACT FROM AUTHOR]

Pomelo sponge layer (PSL) had been considered as a potential source of soluble dietary fiber (SDF), while they were mostly disposed of as waste. To promote high-value utilization of pomelo wastes, this study extracted SDF from PSL of six varieties of pomelo, and their physicochemical, structural and functional properties were investigated. Results indicated that all PSL-SDFs showed good physicochemical and functional properties. Among them, PSL-SDF from grapefruit (GRSDF) showed better water holding capacity and swelling capacity, whereas Shatian pomelo PSL-SDF and Guanxi pomelo PSL-SDF had the highest thermal stability and oil holding capacity, respectively. Furthermore, compared with other PSL-SDFs, GRSDF displayed the lowest hydrolysis degree coupled with the best antioxidant and probiotic growth-promoting abilities. Finally, the correlation analysis showed that multiple beneficial effects of PSL-SDFs were markedly associated with their molecular weight and the concentrations of total phenolic, total flavonoids, rhamnose, galacturonic acid, glucose and arabinose. Collectively, these findings contributed to a better understanding of the physicochemical and functional properties of SDFs extracted from different PSLs, which provided a scientific basis for the development of PSL-SDFs into functional foods. [ABSTRACT FROM AUTHOR]