Abstract: Hydrophobicity and hydrophilicity are incompatible. On a hydrophobic substrate, a macroscopic droplet always exhibits a morphology with contact angle higher than 90∘, never lower than 90∘. In this paper, we theoretically demonstrate the possibility that a nanoscale droplet can exhibit a contact angle lower than 90∘ on the same hydrophobic substrate. To demonstrate this, we analyze the morphology and contact angle of a sessile droplet on smooth flat substrates, taking into account disjoining pressure. By constraining the two-dimensional cylindrical droplet and minimizing the free-energy functional, we derive a formula to determine the droplet’s morphology and the boundary between hydrophilic and hydrophobic contact angle for finite-sized droplets. Using this formulation, we reconsider the formula for the macroscopic contact angle, known as the Derjaguin-Frumkin formula. By utilizing a simple disjoing pressure model, we find that the calculated contact angle at the nanoscale is always smaller than the macroscopic contact angle determined by the Derjaguin-Frumkin formula. Consequently, the wettability (hydropilicity/hydrophobicity) differs at the nanoscale compared to the macroscale. We further discuss the implication of our results on the size-dependent contact angle and line tension at the nanoscale.

Abstract: Lipid vesicles and related nanocarriers often contain two compartments, such as the inner and outer leaflets of a bilayer membrane between which amphipathic molecules can migrate. We develop a stochastic model for describing the transfer kinetics of cargo between the two compartments in an ensemble of carriers, neglecting inter-carrier exchange to focus exclusively on intra-carrier redistribution. Starting from a set of rate equations, we examine the Gaussian regime in the limit of low cargo occupation where Gaussian and Poissonian statistics overlap. We derive a Fokker–Planck equation that we solve analytically for any initial cargo distribution among the carriers. Moments of the predicted distributions and examples, including a comparison between numerical solutions of the rate equations and the analytic solutions of the Fokker–Planck equation, are presented and discussed, thereby establishing a theoretical foundation to study coupled intra- and inter-carrier transport processes in mobile nanocarrier systems.

Abstract: In this study, we investigated the impact of incorporating energetic substituents such as –NO₂, –NH₂, –Cl, –F, N-methyl-N-nitro (CH₃–N–NO₂), and picryl on the detonation performance and stability of acridone-based compounds. The DFT B3LYP/cc-pVTZ method was employed to evaluate key molecular properties, including the HOMO–LUMO gap, cohesive energy, chemical hardness, and electronegativity. Based on these parameters, changes in chemical and thermal stability were assessed. The results highlight the significant influence of both the type and position of substituents on the energetic performance and stability of the compounds studied. Notably, the acridone derivative bearing a picryl group and four –NH₂ substituents exhibited energetic properties superior to those of TNT. However, the analysis of stability and sensitivity—based on oxygen balance—suggests that such substitutions generally reduce stability. This reduction, however, is dependent on both the nature and number of substituents introduced.

Abstract: We resolve palladium’s long-standing Madelung “anomaly” by proving that its ground–state con- figuration, [Kr] 4d¹⁰5s⁰, is the generic outcome of a spectral phase transition in a self–adjoint radial Hamiltonian on Hrad = L²(R+, r²dr). The decisive operator invariant is the asymptotic level V_∞ = μ + Γ0 (r → ∞) of bL = −∇² + Γ(r) + μ. For V_∞ > 0, Hardy control, Birman–Schwinger bounds, and the Rayleigh–Ritz variational form enforce spectral locking in the s channel: the projector Ps selects the trivial amplitude, P_sΨ ≡ 0. Agmon estimates yield an evanescent length λ_s = (V∞ − E)^−1/2; a representative Pd fit gives λs ≈ 0.18 ˚A and > 99.9% suppression of 5s density within r < 0.5 ˚A. The extinction/survival dichotomy is a Z₂ spectral–topological invariant determined solely by sign V∞, with a sharp phase boundary at V∞ = 0. Levinson’s theorem organizes Group 10 systematics as spectral flow across that boundary: Ni sits near the index jump (marginal), Pd lies deep in the extinct phase (Ps = 0), and Pt shows partial reactivation by relativistic softening. A compact, falsifiable classifier, κ(Z) = Z ∞ 0 r μ(Z) + Γ(r; Z)
− dr, provides a parameter–free integral indicator of extinction. Chemically, s–extinction narrows the d manifold, shifts the d–band center toward εF , removes isotropic mixing channels, and explains square–planar preference, d–dominated screening in XPS/ EELS, and vanishing Fermi–contact/Knight terms. The angle–integrated XPS intensity, written in operator form I(ω) ∝ TrD†δ(ω−( bH−EF ))D ρ0 , exhibits null s–resolved weight near threshold in Pd, matching P_sΨ ≡ 0 and anchoring the theory operando. A coarse–grained Landau functional for χs = ∥PsΨ∥² captures amplitude selection and the bifurcation at V_∞ = 0. Finally, V_∞ maps tangible design knobs—alloying, strain, coverage, and support/ligand fields—onto phase control, enabling testable targets (λ_s, a_s, ε_d) for diagnosing and engineering orbital extinction/reactivation across the periodic table.

Abstract: Periodic anomalies in the electronic configurations of transition and related metals have long re- sisted straightforward explanation. Here it is shown that these so-called exceptions are not accidental but arise as quantized, topologically protected features of the atomic spectrum. By formulating the Hamiltonian in terms of spectral branches over parameter space, each anomalous configuration is identified with a singularity—indexed by invariants such as Berry phase, Chern number, or winding number—between distinct symmetry-adapted states. This spectral–topological approach unifies ob- served and predicted anomalies within a single mathematical structure, recasting the periodic table as a landscape of topological transitions rather than empirical rules. The results provide a predictive ex- planation for electronic anomalies and suggest new avenues for the design of materials and quantum systems with tailored properties.

Abstract: Classical Molecular Dynamics simulations were used to investigate the interfacial adsorption of ethane on ultrathin molten polyethylene films. We investigated the interfacial adsorption of supercritical ethane on ultrathin molten polyethylene films at various temperatures (298.15 - 448.15 K) and pressures (0.28 - 13.17 MPa). Ethane was found to accumulate preferentially at the film's interfaces rather than dissolving into the film's core. The ultra-thin, metastable films, studied at their mechanical stability limit, are composed of two overlapping interfaces. The films show some fractions of interfacial chains transiently desorbing from the film surface and entering the gas phase, which facilitates the accumulation of ethane at the interfaces. At 373.15 K and pressures between 0.29 and 9.65 MPa, the combined film interfaces adsorb between 4.8 and 8.6 times more ethane than the amount solubilized in the central, bulk region of the film. Interfacial tension decreases exponentially with increasing gas pressure. Interfacial tension is primarily governed by inter-chain interactions at the interface. Minor contributions arise from the vibrational dynamics of polyethylene chain fractions that transiently desorb from the film surface. Furthermore, the solubility of ethane in the film's bulk region exhibits a temperature-dependent inversion: at 298.15 K, the ethane density in the film's center slightly exceeds that of the bulk gas, but this trend reverses at 373.15 K and becomes more pronounced as the temperature increases. This indicates a potential solubility transition temperature between 298.15 and 373.15 K.

Abstract: Avogadro’s number is one of the profound constants of science—quantifying the relationship between the atomic and macroscopic worlds. This review traces its evolution from theoretical origins and experimental measurement to its exact status as a defining SI constant. Special emphasis is placed on our innovative work based on computational framework for estimating the unified atomic mass unit (UAMU) and Avogadro number. Our approach, grounded in first-principles of nuclear physics and realized in transparent Python algorithms, uniquely relates macroscopic constants directly to nuclear binding energies across a broad range of elements and nuclides. By demonstrating that Avogadro’s number is essentially the inverse of the computed UAMU, and by systematically analysing results from both advanced semi-empirical mass models and our Strong and Electroweak Mass Formula, our approach reveals a deep physical interplay between nuclear saturation and the emergence of Avogadro’s constant. This computational paradigm, adaptable to AI-driven improvements and new nuclear data, offers powerful pedagogical, conceptual, and research benefits, complementing established experimental methods. The review discusses these advances alongside the historical, scientific, and educational significance of Avogadro’s number, and concludes by outlining future prospects at the intersection of nuclear physics, computation, and fundamental metrology. Following a crude approximation, for Z = (1 to 140) having 15504 atomic nuclides, estimated value of the Avogadro number is, (6.017052 to 6.017185) x10^26 atoms/kg. It needs a review with respect to conceptual validation, statistical procedures and python program changes/corrections/updates.

Abstract: We analyze the high-order above-threshold ionization (HATI) process of small polyatomic molecule with C3 symmetry, which is induced by a bicircular strong laser field. This field consists of two coplanar, counter-rotating, circularly polarized components with frequencies rω and sω where r and s are integers. In our study, we use an improved molecular strong-field approximation to obtain electron energy- and angle-resolved spectra of BF3 molecule. We analyze the contributions of individual atoms as well as the impact of molecular symmetries on these spectra. We find that these spectra are significantly affected by the characteristics of the molecule and the laser-field parameters. Furthermore, we observe pronounced interference minima in the HATI spectra. We demonstrate that these minima result from the destructive interference of rescattered wave packets from different atomic centers, and we determine the conditions under which they occur, including two-, three-, and four-center interference.

Abstract: The incorporation of MAX phase interface layers into silicon carbide (SiC) composites has been shown to significantly enhance mechanical properties, particularly under irradiation conditions. However, conventional Ti-based MAX phases suffer from thermal instability and tend to decompose at high temperatures. In this work, Sc₂SnC coating was successfully synthesized on the surface of SiC fibers (SiC_f) via an in-situ reaction between metals and pyrolytic carbon (PyC) in a molten salt environment. The PyC layer, pre-deposited by chemical vapor deposition (CVD), served as both a carbon source and a structural template. Characterization by SEM, XRD, and Raman spectroscopy confirmed the formation of Sc₂SnC coatings with a distinctive hexagonal flake-like morphology, accompanied by an internal ScC_x intermediate layer. By turning the Sc-to-Sn ratio in the molten salt, coatings with varied morphologies were achieved. ScC_x was identified as a critical intermediate phase in the synthesis process. The formation of numerous defects during the reaction enhanced element diffusion, resulting in preferential growth orientations and diverse grain structures in the Sc₂SnC coating.

Abstract: The electrochemical performances of Li-ion batteries based on LiFePO4(LFP) cathode supported by bio sourced activated carbon obtained from Millet Cob (MC) or Water Hyacinth (WH) were determined. The carbons were obtained by combustion prior to drying the raw materials of WH and MC, followed by steps of various chemical cleanings, were activated at the following different mass ratios of potassium hydroxide (KOH) and WH or MC respectively: KOH/WH 1:1, 2:1, and 5:1, and KOH/MC 1:1, 2:1, and 5:1.The physics properties (X-ray diffraction patterns, BET surface area, micropore and mesopore volume, conductivity, etc. ) and electrochemical performances (specific capacity, discharge at various current rates, electrochemical impedance measurement, etc.) were determined. The electrochemical performances of coin cells based on cathodes composed of 85% LiFePO4, 8% of these activated carbons, and 7% polyvinylidene fluoride (PVDF) as a binder, with lithium metal as the anode were studied. Cycling tests and the discharge at different current rates of these cells based on the LiFePO4/C cathodes supported by the various activated carbons were achieved. It was found that the coulombic efficiency, the specific capacity and the discharge at different current densities of these cells were interesting for Li-ion batteries applications. It was shown that their Coulombic efficiency was at least 99% and was very close to that of the cell based on LFP/commercial graphite cathode. The specific capacity of the cells was correlated to the KOH/WH et KOH/MC. Overall, the electrochemical performances of cells based on LFP/MC and LFP/WH were correlated to the physics properties of the activated carbons of MC and WH. Their performances were also compared to those of cells based on LFP/graphite. It was found that cells based on activated carbon obtained from WH exhibited better performances than those from MC. For a given current rate and the same number of cycles, the specific capacity of the cells based on activated carbons of WH is very close to that based on graphite.

Abstract: Toroidal and Klein-bottle fullerenes share a peculiar topological symmetry whose existence has been recently proposed. This symmetry is valid for certain sizes of the lattices. Here some new topological features are presented for a better understanding of the phenomenon between the two polyhexes outside the symmetrical region. Lastly, we introduce here the enhanced-by-topology expansion, an original topological novel effect that arises from the Toroidal / Klein-bottle symmetry.

Abstract: The mean force between two highly like-charged macroions in the presence of monovalent counterions and added multivalent salt, within solvents of varying dielectric constants has been studied using Monte Carlo simulations. Without additional salt, the mean force is strongly repulsive at all macroion separations in solvents with a dielectric constant ϵ_r ≥ 30. However, in solvents having ϵ_r ≤ 30, the macroions experience effective attraction, indicating that attractive interactions between highly charged macroions can occur even without multivalent salt in nonpolar solvents with low dielectric constants. At a multivalent counterion-to-macroion charge ratio of β = 0.075, the mean force becomes attractive at short separations in solvents with ϵ_r = 54 containing 1:3 salt, as well as in all solvents with 1:5 salt, while still exhibiting significant repulsion at longer separations. In contrast, for solvents with 1:3 salt and dielectric constants ϵ_r = 68 and ϵ_r = 78.4, the mean force turns attractive at a higher salt concentration, around β = 0.225. The shift of the mean force to an attractive state at short separations signifies charge inversion on the macroion surface when a sufficient amount of salt is present. At a stoichiometric ratio of multivalent counterions, long-range repulsion vanishes, and attraction becomes significant. However, with excess salt, the strength of the attractive mean force diminishes. Additionally, the attractive force at a given salt concentration increases as the dielectric constant decreases and is stronger in systems with 1:5 salt than in those with 1:3 salt.

Abstract: Chalcone derivatives with intriguing optical and electrochemical properties have been synthesized and systematically studied for their potential as anticancer agents. This article, insights strategically synthesis followed by their spectroscopic, computational, electrochemical, and biological studies of 3-(naphthalen-3-yl)-1-phenylprop-2-en-1-one (3NPEO). The absorption and emission bands witness 320-370 nm and 375–462 nm respectively. The solvatochromic effect was investigated in different solvents of various polarities with significant Stokes shifts (50–87 nm) indicating intramolecular charge transfer (ICT) in the excited state. Molar absorptivity (1.7–4.26 × 10⁴ M⁻¹ cm⁻¹) and fluorescence quantum yields (0.368–0.917) were determined, along with nonlinear optical properties in solution. Cyclic voltammeter is employed to analyze Electrochemical parameters, while quantum chemical calculations (DFT) by B3LYP/G(d,p) in chloroform confirmed promising results with experimental data. Molecular docking and dynamics simulations revealed strong interactions with the progesterone receptor enzyme, supported by structure-activity relationship (SAR) analyses. In vitro cytotoxicity assays on the MDAMB-231 cell line demonstrated moderate tumor cell inhibitory activity, with apoptosis studies confirming early and late apoptosis induction. These results suggest that the title compound holds promise as a potential anticancer agent.

Abstract: We have recently shown that the sphere-in-contact model can be used as an educational and research tool in various contexts, such as the visualization of carbon structures (e.g. graphene, carbon nanotubes, carbon nanocones and graphite), heterogeneous catalysts, metal nanoparticles and organic molecules. In this study we present how it can be used to model the adsorbate structure of a monoatomic elements on the hexagonal close-packed surface of HCP and FCC metals to study long range ordering phenomena of monoatomic adsorbates on metals. We have used atoms of varying radius and colour to represent the metal surface atoms and the adsorbate atoms. The study reveals that many surface configurations are possible for a fixed adsorbate coverage (θ) by the movement of the adsorbate atoms in response to surface adsorbate-adsorbate repulsions. The movement of the particles (e.g. particle diffusion) can be seen directly in the model and this is caused by the user intervention. This has great educational but also research value as one can directly see how the adsorbate atoms reorder on the surface of a metal. We calculate the repulsive interaction energy of adsorbates using the sphere-in-contact model and are able to identify which surface adsorbed configuration is the lowest energy one. We find that this model will be useful in the rational design of catalytic materials and materials coatings with new technological applications where long range ordering of surface adsorbates is essential.

Abstract:

We describe an experiment in which we employ a radiofrequency sensor to measure pH changes in a liquid solution. The experiment is novel in a few ways. First, the sensor does not have contact with the liquid, but rather detects the change from the outside of a PVC pipe. Second, the change is detected using a Linear Discriminant Analysis model using values from an inverse Fourier transform of the frequency data as its features. We believe this to be the first use of Fourier anaylsis in contactless pH measurement using radio frequencies.

Abstract: One of the most challenging issues in catalytic water dissociation hydrogen production technology is understanding the activation mechanism of water. To gain insights into this process, a first-principles molecular dynamics method was used to simulate the catalytic dissociation of H2O on 88 alloy catalysts. The study's results revealed that a larger red shift of the center of the v1 and v3 modes of adsorbed H2O corresponds to a lower dissociation temperature. The resonance absorption of heat from water molecules by the frontier electron promotes the dissociation reaction. Comparing the frontier orbitals of precursors and intermediate states shows that the number of involved frontier orbitals significantly influences the catalytic reaction.

Abstract:

Conical intersections (CIs) are the most efficient channels of photodeactivation and energy transfer, while femtosecond spectroscopy is the main experimental tool delivering information on molecular CI-driven photoinduced processes. In this work, we undertake comprehensive ab initio investigation of the CI-mediated internal conversion in fulvene by simulating evolutions of electronic populations, bond lengths and angles, and time-resolved transient absorption (TA) pump-probe (PP) spectra. TA PP spectra are evaluated on-the-fly, by combining the symmetrical quasi-classical/Meyer-Miller-Stock-Thoss (SQC/MMST) dynamics and the doorway-window representation of spectroscopic signals. We show that the simulated time-resolved TA PP spectra reveal not only the population dynamics but also the key nuclear motions as well as mode-mode couplings. We also demonstrate that TA PP signals are not only experimental observables: They can also be considered as information-rich purely theoretical observables, which deliver more information on the CI-driven dynamics than conventional electronic populations. This information can be extracted by the appropriate theoretical analyses of time-resolved TA PP signals.

Abstract: In this work, we have studied the main decomposition reactions on the ground state of nitromethane (CH3NO2) with the CASPT2 approach. The energetics of the main elementary reactions of the title molecule have been analyzed on the basis of Gibbs free energies obtained from standard expressions of Statistical Thermodynamics. In addition, it is described a mapping method (orthogonalized 3D-representation) for the potential energy surfaces (PESs) by defining an orthonormal basis consisting of two Rn orthonormal vectors (n, internal degrees of freedom) that allows to obtain a set of ordered points in the plane (vector subspace) spanned by such a basis. Geometries and harmonic frequencies of all species and orthogonalized 3D-representations of the PESs have been computed with the CASPT2 approach. It is found that all of the analyzed kinetically controlled reactions of nitromethane are endergonic. For such a class of reactions, the dissociation of nitromethane into CH3 and NO2 is the process with lower acctivation energy barrier (G), that is, the C-N bond cleavage is the most favorable process. In contrast, there exists a dynamically controlled process that evolves through a roaming reaction mechanism and is an exergonic reaction at high temperatures: CH3NO2 [CH3NO2]* [CH3ONO]* CH3O + NO. The above assertions are supported by CASPT2 mappings of the potential energy surfaces (PESs) and semiclassical trajectories obtained by "on-the fly" CASSCF molecular dynamics calculations.

Abstract: A non-linear (non-additive) increase in stability of hexamers follows an increase in the total number of (i) aad (a double proton acceptor) plus add (a double proton donor) waters commonly linked with anticooperativity and (ii) the total number of intermolecularly delocalized electrons (intermolNdeloc) in the 3D space occupied by a hexamer. Subsequently, we obtained nearly a perfect linear correlation between increase in the cluster stability and intermolNdeloc. Individual water molecules that act as either aad or add: (i) delocalize the largest number of electrons throughout a cluster; (ii) are involved in the strongest attractive, hence energy-stabilizing intermolecular interaction with the remaining five waters; (iii) have the most significant quantum component of the intermolecular interaction energy and (iv) relative to six non-interacting water molecules, stabilize a hexamer the most, as quantified by a purposely derived mol-FAMSEC energy term. Clearly, the all-body approach used in the unified, molecular-wide and electron density (MOWeD)-based concept of chemical bonding contradicts the commonly accepted view that aad and add water molecules are involved in anticooperativity in 3D water hexamers. Consequently, we propose here a general definition of cooperativity that should be applicable to any n-membered molecular clusters, namely: the quantifiable, physics- and quantum-based cooperativity phenomenon is synonymous with the intermolecular all-body delocalization of electrons leading to the increase in stability of individual molecules on an n-membered cluster formation.

Abstract: The Second Law of Thermodynamics states that entropy increases in a spontaneous process in an isothermal and isolated system and characterizes the direction of evolution. Real systems are not isolated. Here we suggest the description of progress in non-isolated and influenced by external fields systems. One of these fields is temperature field. In this case only entropy is not enough, and we suggest using a new function Ls, which is analogous to the Lagrangian in classical mechanics. Instead of mechanical kinetic energy, Ls includes the product ST, and the system always evolves towards the increase of this modified Lagrangian Ls. The system reaches an equilibrium when the gradient of a total potential force is balanced by the gradients of entropic and thermal forces. For isolated systems the description is reduced to Second Law and Clausius inequality. It has several advantages in comparison to Onsager’s non-equilibrium thermodynamics. This approach does not need a gradient of chemical potential, and easily explains the basic aspects of Soret thermodiffusion and thermoelectric Peltier-Seebeck and Thomson (Lord Kelvin) phenomena in non-isothermal and non-isolated systems. Inside the black hole balance of gravitational and entropic forces may lead to a steady state or the black hole evaporation.