Chemical Potential Research Articles (Page 1)

Shining light on a mixed ionic-electronic conductor induces variations in both its electronic and ionic behaviors. While optoelectronic processes in semiconductors with negligible ionic conductivities are well understood, the role of mobile ions in photoactive mixed conductors, such as hybrid halide perovskites, is largely unexplored. Here, we propose a model addressing this problem, combining optoelectronics and optoionics. Using methylammonium lead iodide (MAPI) as a model material, we discuss the expected influence of optical bias on the charge carrier chemistry of mixed conductors under steady-state conditions. We show that changes in the concentration of ionic defects under light with respect to the dark case are a direct consequence of their coupling to electrons and holes through the component chemical potential (iodine in the case of MAPI) and the electroneutrality condition. Based on the trend in the quasi-Fermi level splitting in the mixed conductor, we emphasize implications of controlling point defect chemistry for the function and performance optimization of solar energy conversion devices, including those based on halide perovskites. Lastly, we show that, in the presence of multiple redox reactions mediating the ionic and electronic quasi-equilibrium, either positive or negative changes in the ionic defect pair chemical potential can be obtained. These findings indicate the intriguing possibility to increase or reduce ionic defect concentrations in mixed conductors through exposure to light.

This study investigates the mechanical, thermal, and thermodynamic properties of zinc-blende (zb) CdS and CdSe using Density Functional Theory (DFT) within the LDA, PBE, and PBE+U approximations. All three functionals confirm the mechanical stability of both compounds, with PBE+U providing results that best align with available theoretical and experimental data. Based on PBE+U calculations, CdS exhibits higher stiffness (B = 71.75 GPa, E = 36.71 GPa, G = 12.99 GPa) and faster sound velocity (ν= 1828 [Formula: see text]) than CdSe (B = 53.85 GPa, E = 38.88 GPa, G = 14.13 GPa, ν = 1746 [Formula: see text]). Temperature-dependent analyses using the quasi-harmonic approximation reveal anomalous thermal contraction at low temperatures, transitioning to normal expansion beyond the zero thermal expansion points (113.92 K for CdS and 61.50 K for CdSe). The electron chemical potential shows a non-monotonic temperature dependence with transition temperatures of 1483 K for CdS and 853 K for CdSe. Heat capacities approach the Dulong-Petit limit (≈ 49 J [Formula: see text] [Formula: see text]) at high temperatures, with CdSe reaching this limit earlier due to its softer lattice. CdSe also displays higher entropy, consistent with its heavier atomic mass and enhanced anharmonicity. Overall, CdS is mechanically stiffer and thermally more stable, while CdSe exhibits greater vibrational disorder. Overall, CdS is mechanically stiffer and thermally more stable, while CdSe shows greater anharmonicity and entropy.

Aristolochia indica L. belongs to family Aristolochiaceae is a traditional medicinal plant in Indian subcontinent used for the treatment of various diseases ailment. In the present study the antibacterial, antioxidant, chemical profiling of methanolic and hexanoic extract of Aristolochia indica fruit (AIF) were investigated. In- vitro antibacterial assay (Disc diffusion and microbroth dilution method) was performed against Salmonella enterica serovar Typhimurium (ATCC 14028), Escherichia coli (ATCC 25922) and Bacillus cereus (ATCC 11778). Methanolic extract showed the MIC value of 1700 µg/mL, 1800 µg/mL, 1000 µg/mL and hexanoic extract were 1900 µg/mL, 1500 µg/mL, 1200 µg/mL respectively against Salmonella enterica serovar Typhimurium (ATCC 14028), Escherichia coli (ATCC 25922) and Bacillus cereus (ATCC 11778). In vitro radical scavenging activity was estimated by DPPH assay; methanolic and hexane extract exhibited showed IC50 value of 430.5 ± 27.36 µg/mL, 559.2± 8.75 µg/mL with respect to control 3.8 ± 0.24 µg/mL(Ascorbic acid). Liquid Chromatography/Mass Spectrometry (LC/MS) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis was done for chemical components characterization. LC/MS revealed the presence of quercetin, kaempferide, linoleic acid, chlorogenic acid and other bioactive compounds. GC-MS chemical composition revealed the presence of maltol (7.42 %), pyranone (9.02 %), o-coumaric acid (4.34 %), α-monoacetin (6.05 %), mome inositol (9.29 %), tetracontane (27.49 %), campesterin (3.56 %), stigmasterol (3.64 %) and β -sitosterol (13.79 %). The phytochemical analysis based on GC-MS and LC-MS confirmed that the absence of aristolochic acid in Aristolochia indica fruit extracts, compound known to have nephrotoxic effect. The findings indicate that the plant’s fruit could be used as a rich source of antioxidants, antibacterial agents and can be used in pharmaceutics and therapeutics industries.

We determine the possible trajectories the Universe may have followed in the quantum chromodynamics (QCD) phase diagram during the QCD epoch. We focus on the roles of chiral symmetry breaking and pion condensation under high imbalances in lepton asymmetry. Adopting the quark-meson model as an effective description of QCD at finite temperature, charge and baryon chemical potentials we show that, for sufficiently large but physically motivated asymmetries, the Universe may have entered the pion condensation phase through a first-order phase transition, followed by a second-order phase transition when exiting it. Such a first-order phase transition represents a new possible source of primordial gravitational waves during the QCD epoch.

The quasiparticle model is employed to investigate the quark matter at finite chemical potential. The effective bag constant is derived to depend on both the chemical potential and the magnetic field. The self-consistent thermodynamics is satisfied such that the minimum free energy corresponds to zero pressure. It is shown that the strong magnetic field is beneficial for the stabilization of the strange quark matter. However, the increase in the vacuum bag constant could reduce the stability. We propose that for the absolutely stable strange quark matter, there is a lower limit of the allowed magnetic field, which competes with the vacuum bag constant.

This study focuses in determining the pyrolysis kinetics for the husk of the Corylus avellana grown in Chile as a first step for determining the energy and chemical potential, and as an alternative of the disposal method of this biowaste in Chile. Thermogravimetric analysis (TGA) was performed on hazelnut husk sample at heating rates of 10, 20, 30, and 40 °C/min under nitrogen atmosphere (50 mL/min). The results were analyzed using three different kinetic models to determine the activation energy (Ea) and pre-exponential factor (A): the isoconversional methods of Kissinger-Akahira-Sonose (KAS), Ozawa-Flynn-Wall (OFW), and the Coats-Redfern method. The TGA results revealed a multi-stage pyrolysis process, beginning with dehydration and followed by the decomposition of hemicellulose and cellulose, culminating the formation of char (lignin content). The analysis demonstrated a clear dependence of the decomposition rate on heating rate, with faster heating rates resulting in higher peak temperatures. This effect is attributed to variations in heat transfer efficiency within the biomass particles. Applying the KAS and OFW isoconversional methods yielded an average activation energies of 121 kJ/mol and 126 kJ/mol. The Coats-Redfen method provided the corresponding pre-exponential factors. A detailed analysis of the activation energy and pre-exponential factor as a function of conversion degree was performed, revealing a non-linear relationship and providing insights into the reaction mechanism of the hazelnut husk. A comparative analysis with existing literature on the pyrolysis of similar biomass showed good agreement between the results obtained in this study and previously published data. Understanding the thermal behavior of the hazelnut husk offers a key information for the design and optimization of bioenergy and bio-chemical processes utilizing this underutilized resource.

Abstract The kagome lattice provides a playground to explore novel correlated quantum states due to the presence of flat bands in its electronic structure. Recently discovered layered kagome compound Nb3Cl8 has been proposed as a Mott insulator coming from the half-filled flat band. Here we have carried out systematic transport study to uncover the evidence of Mott insulator in Nb3Cl8 thin flakes. Bipolar semiconducting property with Fermi level close to conduction band has been revealed. We have further probed the chemical potential of Nb3Cl8 by tracing the charge neutrality point of monolayer graphene proximate to Nb3Cl8. The gap of Nb3Cl8 flakes is approximately 1.10 eV at 100 K and shows pronounced temperature dependence, decreasing substantially with increasing temperature to ∼0.63 eV at 300 K. The melting behavior of the gapped state is in consistent with theoretically proposed Mott insulator in Nb3Cl8. Our work has demonstrated Nb3Cl8 as a promising platform to study strongly correlated physics at relatively high temperature.

Abstract This essay presents an examination of the rise and evolution of quantum mechanics, approached from a chemical viewpoint. The emergence of quantum mechanics have led to significant progress and discoveries in chemistry, offering well grounded and rigorous concepts to rationalize the observed behavior of matter. Quantum chemistry’s progress is credited to the application of quantum mechanics in molecular systems, with the objective of characterizing their electronic structures and elucidating their properties and reactivity. The link between the reactivity principles that govern the behavior of matter in classical chemistry and specific global electronic properties identified in quantum chemistry is well recognized. Notably, the electronic chemical potential is highlighted as a crucial property for uncovering the nature of matter and its chemical transformation processes. It plays an essential role in influencing molecular reactivity and is crucial for evaluating reaction mechanisms through its first derivative, known as the reaction electronic flux. In addition, the local baseline electronic activity within molecular systems is briefly examined, this is a nonreactive electronic activity that arises from the vibrational dynamics intrinsic to molecular systems, it is also characterized via the electronic chemical potential, thus confirming the relevance of the later property in chemistry.

The solvatochromic effect and dipole moment characteristics of 4-(2-iodo-phenoxymethyl)-6-methoxy-chromen-2-one (PM6C) and 4-(2-iodo-phenoxymethyl)-7-methoxy-chromen-2-one (PM7C) were examined at room temperature using absorption and emission spectra in a series of solvents with increasing polarity. Stokes shift obtained from spectral data is found to be bathochromic in nature for both the molecules, indicating π-π* transitions. The ground state and excited state dipole moments of PM6C and PM7C were determined by the means of Lippert-Mataga, Bakhshiev, Kawaski-Chamma-Viallet, and Reichardt's solvent polarity functions. Excited state dipole moments were found to be larger than the ground state dipole moment due to significant redistribution of the π-electron density in more polar excited state. Computational examination using the density functional theory (DFT) method validates the results calculated through solvent polarity functions. The HOMO and LUMO energy bands obtained by DFT approach are found be in good agreement with cyclic voltammetry data. The energy gap, chemical hardness (ɳ), chemical softness (s), ionization potential (IP), electron affinity (EA), electronegativity (χ), electrophilicity (ω), and chemical potential (µ) of the molecules were estimated using the values of HOMO and LUMO energy bands. The electrical conductivity and charge transport characteristics of the synthesized molecules are studied through A.C Impedance behaviour. This study gives comprehensive understanding of the molecules involvement in an optoelectronic device.

Abstract The thermodynamic properties of an ideal bosonic system composed of particles and antiparticles at finite temperatures are examined within the framework of a scalar field model. It is assumed that particle–antiparticle pair creation occurs; however, the system is simultaneously subject to exact charge (isospin) conservation. To implement this constraint, we first consider the system within the Grand Canonical Ensemble and then transform to the Canonical Ensemble using a Legendre transformation. This procedure provides a formally consistent scheme for incorporating the chemical potential at the microscopic level into the Canonical Ensemble framework. To enforce exact conservation of charge (isospin, N I ), we further analyze the thermodynamic properties of the system within the extended Canonical Ensemble , in which the chemical potential becomes a thermodynamic function of the temperature and conserved charge. It is shown that as the temperature decreases, the system undergoes a second-order phase transition to a Bose–Einstein condensate at the critical temperature T c , but only when the conserved charge is finite, N I = const ≠ 0. In a particle–antiparticle system, the condensate forms exclusively in the component with the dominant particle number density, which determines the excess charge. We demonstrate that the symmetry breaking of the ground state at T = 0 results from a first-order phase transition associated with the formation of a Bose–Einstein condensate . Although the transition involves symmetry breaking, it is not spontaneous in the strict field-theoretic sense, but is instead induced by the external injection of particles. Potential experimental signals of Bose–Einstein condensation of pions produced in high-energy nuclear collisions are briefly discussed.

Molecular wires represent a cornerstone of next-generation nanoelectronics, yet the design of highly efficient, short molecular conductors remains a significant challenge. In this study, we present a catalyst-free, green synthetic route for the preparation of anilino-1,4-naphthoquinone enaminone derivatives via aqueous-phase Michael addition between anilines and 1,2-naphthoquinone-4-sulfonic acid sodium salt. The reaction proceeds rapidly at room temperature, yielding products with excellent efficiency (96–98%) and exceptional purity, as confirmed by comprehensive spectroscopic characterization (FT-IR, UV-Vis, 1H and 13C NMR, MS) and elemental analysis. Single-crystal X-ray diffraction further validated the molecular structures of representative compounds. Theoretical investigations using Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) provided deep insights into the electronic properties and charge transport behavior of these systems. Key analyses included cohesive energy calculations, UV-Vis exciton energy profiles, frontier molecular orbital energies (HOMO/LUMO), chemical reactivity descriptors (hardness, softness, chemical potential), and dipole moment variations under external electric fields (0-140 × 10− 4 a.u.). Additionally, localized orbital locator (LOL) contours, electron density Laplacians, and current-voltage (I–V) characteristics based on Landauer theory were evaluated to assess charge transport efficiency. Comparative analysis reveals that extending the π-conjugation in a molecular system markedly improves its electronic properties, leading to lower energy gaps, enhanced conductance, and greater field responsiveness, which are critical for molecular wire functionality. Furthermore, this work combines sustainable synthesis with advanced computational modeling to offer a robust framework for the design and evaluation of short molecular wires for nanoelectronic devices.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-22175-z.

When two molecular species with mutual affinity are mixed together, various self-assembled phases can arise at low temperature, depending on the shape of like and unlike interactions. Among them, stripes-where layers of one type are regularly alternated with layers of another type-hold a prominent place in materials science, occurring, for example, in the structure of superconductive doped antiferromagnets. Stripe patterns are relevant for the design of functional materials, with applications in optoelectronics, sensing, and biomedicine. In a purely classical setting, an open question pertains to the features that spherically symmetric particle interactions must have to foster stripe order. Here, we address this challenge for a lattice-gas mixture of two particle species, whose equilibrium properties are exactly determined by Monte Carlo simulations with Wang-Landau sampling, in both planar and spherical geometry and for equal chemical potentials of the species. Somewhat surprisingly, stripes can emerge from largely different off-core interactions, featuring various combinations of repulsive-like interactions with a predominantly attractive unlike interaction. In addition to stripes, our survey also unveils crystals and crystal-like structures, cluster crystals, and networks, which considerably broaden the catalog of possible patterns. Overall, our study demonstrates that stripes are more widespread than generally thought, as they can be generated by several distinct mechanisms, thereby explaining why stripe patterns are observed in systems as diverse as cuprate materials, biomaterials, and nanoparticle films.

Approaching drug release performance from mesoporous silica formulations by modeling of chemical potentials.

Based on the principle of corresponding states and using modern physical databases, the dependences of the isobaric coefficient of volumetric expansion on temperature, pressure, and chemical potential for water and argon were compared. These comparisons were made along the gas–liquid and liquid–solid state coexistence curves. It has been shown that there is a region of thermodynamic similarity for water and argon. However, there is also a region of thermodynamic parameters in which water has a number of thermodynamic anomalies. In particular, a loop of temperature dependencies of the isobaric coefficient of volumetric expansion gas–liquid and liquid–ice is observed. An anticorrelation of volume–entropy fluctuations on the line of phase transitions liquid–ice 1 h and two maxima on the line of phase transitions liquid–ice 1 h and liquid–ice V are also observed.

Unveiling the chlorinated aliphatic hydrocarbon contaminants sensing properties of the biphenylene network through DFT calculations.

Context: Demographic forecasts suggest that new cancer cases may reach 35 million by 2050, underscoring the need for innovative, regionally tailored control strategies. Mangroves have yielded multiple potential anticancer compounds in recent years; however, no bibliometric investigation of their role has been conducted. Aims: To provide a bibliometric overview of research on anticancer activity from mangroves. Methods: Keywords related to anticancer activity and mangroves to search the Scopus database were used. VOSviewer and Biblioshiny were used for further analysis. Results: Eighty-seven studies on cancer-associated mangroves were identified, with an annual growth rate of 9.89%. Publications have increased since 2005, reaching a peak in 2020. The top five countries and organizations in productivity were China, India, Indonesia, Malaysia, and Thailand. The top five affiliations were Guangdong Medical University, Shanghai Jiao Tong University, Sun Yat-Sen University, Wuhan University, and Guangdong University of Technology. Wu X, Liu J, Basyuni M, and Tang X were the most prolific authors. Five primary study themes emerged: antineoplastic activity, mangroves, apoptosis, cell proliferation, and protein expression. Conclusions: Recent results indicate a growing interest in the anticancer potential of mangrove bioactive chemicals, which regulate multiple protein expression signaling pathways. This increase in study emphasizes the significance of mangrove bioactive compounds in cancer research.

Chemical characterizations, antioxidant potential and antibacterial efficacy of propolis and postbiotic metabolites against gastrointestinal bacterial pathogens.

Induced long-term potentiation improves synaptic stability and restores network function in ALS motor neurons.

Chemical characterization, nutritional profile, and cytotoxicity potential of Amazonian Theobroma sylvestre Mart. fruits

New artificial neural network models for risk assessment of skin sensitization using amino acid derivative assay, KeratinoSens™, human cell line activation test and in silico structural alert parameter.