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Fluorine-containing flavin derivatives can be used as probes in flavin-binding proteins forming radical pairs to exploit the photo-chemically induced dynamic nuclear polarization (photo-CIDNP) effect. Knowledge of the hyperfine structure is crucial for studying the mechanism of intramolecular radical-pair formation in proteins. Transient 19F photo-CIDNP NMR has so far not been used to determine the isotropic hyperfine coupling constants of 19F nuclei. Here, we show that this method provides reliable results by studying three monofluorinated flavin mononucleotide (FMN) derivatives in conjunction with 6-fluoro-tryptophan. Combining this method with transient 1H photo-CIDNP spectroscopy leads to a more accurate interpretation of the intermediate radical species forming a radical pair. The gathered information can be used to identify the most promising FMN derivative for usage as a probe for formation of radical pairs in proteins. [ABSTRACT FROM AUTHOR]

Correlated orbital theory (COT) is an exact one-particle treatment that adds essential electron correlation into its molecular orbitals, potentially reducing correlated treatments of response properties to one-particle coupled-perturbed Hartree–Fock- or Kohn–Sham-like calculations. Such a computation is vastly simpler than the usual ab initio correlated approach that would add correlation typically with EOM-CC after a perturbed mean-field solution. The question then is, how well can this be accomplished via the Quantum Theory Project (QTP) exchange–correlation (XC) functionals that are meant to emulate the rigorous COT framework? This paper addresses this question for response properties by making comparisons between such orbital-specific calculations and those from well-correlated EOM-CC solutions for static polarizabilities, nuclear magnetic resonance coupling constants, and chemical shifts. The simple orbital-specific version provides an accurate realization of the correlated EOM-CC results, but now in a mode that facilitates an orbital-by-orbital interpretation. Here, we compare 33 XC functionals from the different Jacob's ladder rungs always against the EOM-CCSD results. Thus, the smallest mean absolute deviation for the static polarizability comes from LC-QTP XC, 0.28 a.u. Regarding the total nuclear spin–spin coupling constants, QTP01 performs best, %Error = 10.63% (QTP02 and LC-QTP are second and third best). Finally, the XC that stood out in the chemical shift analysis was TPSS0, which presented the best result for the majority of the chemical shifts. However, considering the overall performances based on linear fitting of all isotope data points, five functionals are recommended for a chemical shift study: TPSS0, ωB97X, QTP00, QTP01, and QTP02, all presenting R2 = 0.96. [ABSTRACT FROM AUTHOR]

A simplified theoretical description of multiple-quantum excitation and mixing for nuclear magnetic resonance of half-integer quadrupolar nuclei is presented. The approach recasts the multiple-quantum nutation behavior in terms of reduced excitation and mixing curves through a scaling of the first-order offset frequency by the quadrupolar coupling constant. The two-dimensional correlation of the static first-order anisotropic line shape to the second-order anisotropic magic-angle-spinning (MAS) line shape is utilized to transform the three-dimensional integral over the three Euler angles into a single integral over the dimensionless first-order offset parameter. These transformations lead to a highly efficient algorithm for simulating the multiple-quantum (MQ)-MAS spectrum for arbitrary excitation and mixing radio frequency (RF) field strengths, pulse durations, and MAS rates within the static limit approximation, which is defined in terms of the rotation period, pulse duration, RF field strength, and quadrupolar coupling parameters. This algorithm enables a more accurate determination of the relative site populations and quadrupolar coupling parameters in a least-squares analysis of MQ-MAS spectra. Furthermore, this article examines practical considerations for eliminating experimental artifacts and employing affine transformations to improve least-squares analyses of MQ-MAS spectra. The optimum ratio of RF field strength to the quadrupolar coupling constant and the corresponding pulse durations that maximize sensitivity within experimental constraints are also examined. [ABSTRACT FROM AUTHOR]

Several N-heterocyclic carbenes (NHCs) are experimentally observed upon the addition of muonium (Mu), and the hyperfine coupling constants (HFCCs) of muon are measured. Theoretical investigation of Mu has been challenging due to significant quantum effects. Herein, we performed an ab initio path integral molecular dynamics (PIMD) simulation, which accurately considers multi-dimensional quantum effects, to theoretically investigate muoniated 1,3-dihydro-2H-imidazole-2-ylidene (Mu-IY). Our findings indicate that quantum effects have two contradictory contributions: the quantum effect of bond vibrations increases the HFCC values, whereas that of out-of-plane angular vibrations decreases the HFCC values. Moreover, we show that the HFCC values of other NHCs can be predicted without the PIMD simulations by applying the structural changes caused by the quantum effect derived from the PIMD simulations of Mu-IY. [ABSTRACT FROM AUTHOR]

Fluctuations in energy gap and coupling constants between chromophores can play an important role in absorption and energy transfer across a collection of two-level systems. In photosynthesis, light-induced quantum coherence can affect the efficiency of energy transfer to the designated "trap" state. Theoretically, the interplay between fluctuations and coherence has been studied often, employing either a Markovian or a perturbative approximation. In this study, we depart from these approaches to incorporate memory effects by using Kubo's quantum stochastic Liouville equation. We introduce the effects of decay of the created excitation (to the ground state) on the desired propagation and trapping that provides a direction of flow of the excitation. In the presence of light-induced pumping, we establish a relation between the efficiency, the mean survival time, and the correlation decay time of the bath-induced fluctuations. A decrease in the steady-state coherence during the transition from the non-Markovian regime to the Markovian limit results in a decrease in efficiency. As in the well-known Haken–Strobl model, the ratio of the square of fluctuation strength to the rate plays a critical role in determining the mechanism of energy transfer and in shaping the characteristics of the efficiency profile. We recover a connection between the transfer flux and the imaginary part of coherences in both equilibrium and excited bath states, in both correlated and uncorrelated bath models. We uncover a non-monotonic dependence of efficiency on site energy heterogeneity for both correlated and uncorrelated bath models. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) Janus transition metal dichalcogenides MXY manifest novel physical properties owing to the breaking of out-of-plane mirror symmetry. Recently, the 2H phase of MoSH has been demonstrated to possess intrinsic superconductivity, whereas the 1T phase exhibits a charge density waves state. In this paper, we have systematically studied the stability and electron–phonon interaction characteristics of MoSLi. Our results have shown that both the 2H and 1T phases of MoSLi are stable, as indicated by the phonon spectrum and the ab initio molecular dynamics. However, the 1T phase exhibits an electron–phonon coupling constant that is twice as large as that of the 2H phase. In contrast to MoSH, the 1T phase of MoSLi exhibits intrinsic superconductivity. By employing the ab initio anisotropic Migdal-Eliashberg formalism, we have revealed the two-gap superconducting nature of 1T-MoSLi, with a transition temperature (Tc) of 14.8 K. The detailed analysis indicates that the superconductivity in 1T-MoSLi primarily originates from the interplay between the vibration of the phonon modes in the low-frequency region and the dz2 orbital. These findings provide a fresh perspective on superconductivity within Janus structures. [ABSTRACT FROM AUTHOR]

The Skyrmion Hall Effect (SkHE) observed in ferromagnetic and ferrimagnetic (FI) skyrmions traveling due to a spin-polarized current can be a problematic issue when it comes to technological applications. By investigating the properties of FI skyrmions in racetracks through computational simulations, we have described the nature of their movement based on the relative values of the exchange, Dzyaloshinskii–Moriya, and anisotropy coupling constants. Beyond that, using a design strategy, a magnetic channel-like nano-device is proposed in which a spin-polarized current protocol is created to successfully control the channel on which the skyrmion will travel without the adverse SkHE. Additionally, a simple adjustment in the current strength can modify the skyrmion position sideways between different parallel channels in the nanostripe. [ABSTRACT FROM AUTHOR]

The escape dynamics of sticky particles from textured surfaces is poorly understood despite importance to various scientific and technological domains. In this work, we address this challenge by investigating the escape time of adsorbates from prevalent surface topographies, including holes/pits, pillars, and grooves. Analytical expressions for the probability density function and the mean of the escape time are derived. A particularly interesting scenario is that of very deep and narrow confining spaces within the surface. In this case, the joint effect of the entrapment and stickiness prolongs the escape time, resulting in an effective desorption rate that is dramatically lower than that of the untextured surface. This rate is shown to abide a universal scaling law, which couples the equilibrium constants of adsorption with the relevant confining length scales. While our results are analytical and exact, we also present an approximation for deep and narrow cavities based on an effective description of one-dimensional diffusion that is punctuated by motionless adsorption events. This simple and physically motivated approximation provides high-accuracy predictions within its range of validity and works relatively well even for cavities of intermediate depth. All theoretical results are corroborated with extensive Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

The ground state of 3d1 MnO42− was studied by density functional theory (DFT) and complete active space self-consistent field (CASSCF) methods in terms of a variety of molecular point group structures to ascertain the site and Jahn–Teller (JT) distortion effect. Modeling results from UB3LYP/6-31+G(d) calculations with natural bond orbital analysis show the four Mn–O bonds are coordinate covalent. The one-electron matrix elements from CASSCF(AILFT) (ab initio ligand field theory) with a second order perturbation treatment were used to calculate the parameters of the angular overlap model. These allowed the calculation of JT stabilization energies and first and second order JT coupling constants for MnO42− with C2v and D2d symmetry. Absorption spectra and excited state transition energies were calculated assuming the lattice distorted geometry was C2v with time-dependent DFT (TDDFT) using the unrestricted coulomb-attenuating UCAM-B3LYP density functional and with the spin-adapted spin-flip DFT using the UBH&HLYP density functional, both with the AUG-CC-PVTZ basis set. The mean absolute deviation of the calculations from experimental excited states for the ligand field and ligand-to-metal charge transfer (LMCT) bands was better than 0.1 eV. Several new assignments for LMCT excited states were made on the basis of the TDDFT excitation results. [ABSTRACT FROM AUTHOR]

Cyclopropylchloromethyldifluorosilane, c-C3H5SiF2CH2Cl, has been synthesized, and its rotational spectrum has been recorded by chirped-pulse Fourier transform microwave spectroscopy. The spectral analysis of several isotopologues indicates the presence of two distinct conformations in the free-jet expansion, which are interconvertible through a rotation of the chloromethyl group. A partial substitution structure is presented for the lower energy conformation and is compared to the equilibrium structure obtained from quantum chemical calculations. Additionally, the presence of the chlorine nucleus leads to the rotational transitions splitting into multiple hyperfine components and χaa, a measure of the electric field gradient along the a axis, is unusually small at merely +0.1393(73) MHz. Various common ab initio and density functional theory methods fail to predict good quadrupole coupling constants (in the principal axis system) that adequately reproduce the observed hyperfine splitting, although diagonalizing the quadrupole coupling tensor from the principal axis system into a nucleus-centered axis system reveals that, overall, these methods calculate reasonably the electric field gradient about the chlorine nucleus. Finally, a total of nine electric dipole forbidden, quadrupole allowed transitions are observed in the rotational spectra of the parent species of the higher energy conformation and the 37Cl isotopologue of the lower energy conformation. These include those of x-type (no change in parity of Ka or Kc), which, to our knowledge, is the first time such transitions have been observed in a chlorine-containing molecule. [ABSTRACT FROM AUTHOR]

In density-functional theory, the exchange–correlation (XC) energy can be defined exactly through the coupling-constant (λ) averaged XC hole n ̄ xc (r , r ′ ) , representing the probability depletion of finding an electron at r′ due to an electron at r. Accurate knowledge of n ̄ xc (r , r ′ ) has been crucial for developing XC energy density-functional approximations and understanding their performance for molecules and materials. However, there are very few systems for which accurate XC holes have been calculated since this requires evaluating the one- and two-particle reduced density matrices for a reference wave function over a range of λ while the electron density remains fixed at the physical (λ = 1) density. Although the coupled-cluster singles and doubles (CCSD) method can yield exact results for a two-electron system in the complete basis set limit, it cannot capture the electron–electron cusp using finite basis sets. Focusing on Hooke's atom as a two-electron model system for which certain analytic solutions are known, we examine the effect of this cusp error on the XC hole calculated using CCSD. The Lieb functional is calculated at a range of coupling constants to determine the λ-integrated XC hole. Our results indicate that, for Hooke's atoms, the error introduced by the description of the electron–electron cusp using Gaussian basis sets at the CCSD level is negligible compared to the basis set incompleteness error. The system-, angle-, and coupling-constant-averaged XC holes are also calculated and provide a benchmark against which the Perdew–Burke–Ernzerhof and local density approximation XC hole models are assessed. [ABSTRACT FROM AUTHOR]

We explore a holographic superconductor model in which a real scalar field is nonminimally coupled to a gauge field. We consider several types of the nonminimal coupling function h(ψ) including exponential, hyperbolic (cosh), power-law, and fractional forms. We investigate the influences of the nonminimal coupling parameter α on condensation, critical temperature, and conductivity. We can categorize our results in two groups. In the first group, conductor/superconductor phase transition is easier to occur for larger values of α, while in the second group stronger effects of the nonminimal coupling makes the formation of scalar hair harder. Although the real and imaginary parts of conductivity are impressed by different forms of h(ψ), they follow some universal behaviors such as connecting with each other through Kramers–Kronig relation in ω → 0 limit or the appearance of gap frequency at low temperatures around ωg ∼ 8Tc, which shifts to larger values by increasing the strength of α. Among all forms of h(ψ) we observe that h(ψ) = 1 + αψ2 gives us better information in wide range of nonminimal coupling constant and temperature. Choosing the best form of h(ψ), we construct a family of solutions for holographic conductor/superconductor phase transitions to discover the effect of the hyperscaling violation when the gauge and scalar fields are nonminimally coupled. we find that the critical temperature increases for higher effects of hyperscaling violation θ and nonminimal coupling constant α. By increasing these two parameters, we obtain lower values of condensation which means that conductor/superconductor phase transition will acquire easier. Furthermore, we understand that the hyperscaling violation affects the conductivity σ of the holographic superconductors and changes the expected relation in the gap frequency. Some universal behaviors like infinite DC conductivity are observed. In addition, we consider a five-dimensional Gauss–Bonnet (GB) black hole with a flat horizon. We find out that the critical temperature decreases for larger values of GB coupling constant, λ, or smaller values of nonminimal coupling constant, α, which means that the condensation is harder to form. Moreover, we study the electrical conductivity in the holographic setup. We observe that the gap frequency shifts to larger values for stronger λ, and becomes flat by increasing α. [ABSTRACT FROM AUTHOR]

The coupling constants of ρ meson-nucleon and ω meson-nucleon are connected through the isospin relation. Using the soft-wall model of holographic QCD, the current work aims to examine the violation (if any) of isospin symmetry of the ω -meson as well as the temperature dependency of the ω -meson- Δ and ω -meson-nucleon- Δ baryon coupling constants. Applying the temperature-dependent profile functions of the vector and fermion fields to the expression of the coupling constants in the model yields the temperature dependence of the coupling constants. The minimum and magnetic type interactions between vector and fermion fields in 5-dimensional AdS space-time are included in the written interaction Lagrangian terms. The temperature dependence of the coupling constants g ω N N (T) , g ω Δ Δ (T) , and g ω N Δ (T) has been investigated. Comparing g ω N N (T) with the coupling constant g ρ N N (T) , it is found that the isospin symmetry of the ω and ρ mesons is not violated at the finite temperature. It is also observed that the coupling constant of the ω meson with baryons decreases as the temperature increases, and this coupling constant becomes zero near the confinement-deconfinement phase transition temperature. [ABSTRACT FROM AUTHOR]

We find new classes of the dynamical black hole solutions in five- or higher-dimensional Einstein–Maxwell-dilaton theory, in which the dilaton field interacts nontrivially with the Maxwell field, and the cosmological constant, with two arbitrary coupling constants. The solutions which are nonstationary, and almost conformally regular everywhere, are constructed by embedding the four-dimensional self-dual geometries. We consider three different situations, where the two coupling constants are not equal, are nonzero equal and finally both are zero. We also consider the cases where one of the metric functions, depends on one coordinate only, and another interesting case where it depends on two spatial coordinates. We also find that the cosmological constant can take all possible negative, zero and positive values, hence our solutions are asymptotically anti-de Sitter, flat and de Sitter. We discuss the properties of the solutions which are the analytic description of coalescing black holes in any dimensions, greater or equal to five. [ABSTRACT FROM AUTHOR]

This article addresses both the existence and properties of non-trivial solutions for a system of coupled Ginzburg-Landau equations derived from nematic-superconducting models. Its main goal is to provide a thorough numerical description of the region in the parameter space containing solutions that behave as a mixed (non trivial) nematic-superconducting state along with a rigorous proof for the existence of this region. More precisely, the rigorous approach establishes that the parameter space is divided into two regions with qualitatively different properties, according to the magnitude of the coupling constant: for small values (weak coupling), there is a unique non-trivial solution, and for large values (strong coupling), only trivial solutions exist. In addition, using a shooting method-based numerical approach, the profiles for the nematic and superconducting components of the non trivial solution are given, together with an algorithm computing the transition values representing the boundaries for the weak coupling region: from superconducting to mixed, and from mixed to nematic. Finally, numerical evidence is given for the existence of a third region, related to neither a small nor a strong coupling parameter (medium coupling) for which multiple non trivial solutions exist. • We provide a rigorous model for the nematic-superconducting phenomena. • We rigorously establish the existence of thresholds. • We design algorithms to compute the numerical values of these thresholds. • We give a detailed description of the mixed nematic-superconducting solutions belonging to the weak coupling regime. [ABSTRACT FROM AUTHOR]

This study is dedicated to the description of the polarized Bjorken sum rule, based on recently derived formulas within the analytic QCD approach. To accommodate the photoproduction limit and incorporate the Gerasimov–Drell–Hearn and Burkhardt-Cottingham sum rules, we develop a new representation for the twist-2 part of the Bjorken sum rule. The derived results were applied for processing of experimental data. We observed a good agreement between the experimental data and the predictions from analytic QCD. In contrast, there is a significant discrepancy between these data and the fitting curves within the standard perturbative approach. [ABSTRACT FROM AUTHOR]

This research studies primarily centers around a specific vacuum solution of the Einstein’s field equations with a negative cosmological constant, known as a type-D vacuum solution in Anti-de Sitter (AdS) background. The key finding of this study is that the determinant of the Ricci tensor (Rμν) possesses a nonzero value. This observation ensures that this vacuum spacetime can be investigated within the framework of Ricci-inverse gravity as well. In fact, it has demonstrated that this type-D vacuum solution serves as an exact solution in Ricci inverse gravity in the background of AdS space. Notably, the negative cosmological constant undergoes modification by the coupling constant within this context. Moreover, we show that this gravity theory permits the formation of closed time-like curves at a specific moment in time analogue to the general relativity case. Consequently, this theory introduces an intriguing time-machine model within the domain of Ricci-inverse gravity theory. [ABSTRACT FROM AUTHOR]

This study explored the evolution of nonlinear eigenmodes in coupled optical systems supported by PT-symmetric Rosen–Morse complex potential, in which one channel is with gain and the other is with loss. We assessed that the threshold potential above which PT-symmetry breakdown occurs is enhanced by coupling constant, by examining low- and high-frequency eigenmodes of ground and first excited states. The stability of eigenmodes was verified by stability analysis using Bogoliubov–de-Gennes (BdG) equations and it was established that even though the Rosen–Morse potential-supported system can create eigenmodes, it cannot support stable soliton solutions for any potential values. The investigation was extended using the modified Rosen–Morse potential that is nearly PT-symmetric and deduced the conditions for better-defined thresholds, improved damping of growth of perturbation which destabilizes eigenmodes, and advanced control mechanisms to manage perturbations and potential interactions. Propagation dynamics of the eigenmodes and power switching between channels have been studied and the controlling mechanism has been discussed to use coupled systems as optical regulators to precisely direct light between multiple paths. We have explored the significance of couplers in signal-processing applications because they control the intensity of various frequency modes. Optical couplers can be used to develop devices that let light travel in one direction while restricting it in the other which find applications in optical sensing. [ABSTRACT FROM AUTHOR]

The CMS experiment provides measurements of the soft and hard QCD processes using samples of proton–proton and AA collisions collected at different energies. Measurements include particle multiplicity, particle momentum spectra and correlations, jet properties and production rates, and are compared with predictions of theoretical models at leading, next-to-leading and next-next-to-leading QCD fixed order accuracy. The data in combination with measurements obtained by other experiments are used to measure the strong coupling constant and for PDF constraints. [ABSTRACT FROM AUTHOR]

We study the thermodynamic geometry of two types of asymptotically anti-de Sitter black holes in four-dimensional Einsteinian cubic gravity, including the uncharged rotating and charged non-rotating black holes, applying the Ruppeiner thermodynamic geometry method. The divergence of the scalar curvature of the Ruppeiner metric ( R R ) is found to be related to the vanishing of the heat capacity. The stability of the solutions is shown to be affected by the Einsteinian cubic gravity coupling constant λ. In the unstable phase of the rotating black hole, the R R appeared to possess additional diverging points, where the number of these points and the behavior of R R are controlled by the angular momentum parameter. Also, for the charged non-rotating black hole case, we show that depending on the values of λ , the solution may enjoy two types of phase transition and R R behaviors. The characteristic behavior of R R of these two types of black holes enabled us to recognize the types of interactions between microscopic degrees of freedom. [ABSTRACT FROM AUTHOR]

[011] poled relaxor-PT single crystals provide superior piezoelectric constants and electromechanical coupling factors in the 32 crystal directions, and also exhibit high electrical stability under compressive stresses and temperature changes. In particular, Mn-doped Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (Mn:PIN-PMN-PT) single crystals show a superior coercive field (EC ≥ 8.0 kV/cm) and mechanical quality factor (Qm ≥ 1030), making them suitable for high-power transducers. The high-power characteristics of [011] poled single crystals have been verified from a material perspective; thus, further investigation is required from a transducer perspective. In this study, the high-power characteristics of piezoelectric transducers based on [011] poled PIN-PMN-PT and [011] poled Mn:PIN-PMN-PT single crystals were investigated. To analyze the driving limits of the single crystals, the polarization–electric field (P–E) curves, as a function of the driving electric field, were measured. The results showed that [011] poled Mn:PIN-PMN-PT single crystals demonstrate lower energy loss and THD (Total Harmonic Distortion), directly relating to the driving efficiency and linearity of the transducer. Additionally, [011] poled Mn:PIN-PMN-PT crystals provide excellent stability under the compressive stress and temperature changes. To analyze the high-power characteristics of [011] poled single-crystal transducers, two types of barrel-stave transducers, based on [011] poled PIN-PMN-PT and [011] poled Mn:PIN-PMN-PT, were designed and fabricated. The changes in the impedance and transmitting voltage response with respect to the driving electric fields were measured, and the energy loss and THD of the transducers with respect to the driving electric fields were examined to assess the driving limit of the [011] poled single-crystal transducer. The high-power characteristic tests confirmed the stability of [011] poled Mn:PIN-PMN-PT single crystals and verified their potential for high-power transducer applications. [ABSTRACT FROM AUTHOR]

In this work an approximate analytic expression for the quantum partition function of the quartic oscillator described by the potential V (x) = 1 2 ω 2 x 2 + g x 4 is presented. Using a path integral formalism, the exact partition function is approximated by the partition function of a harmonic oscillator with an effective frequency depending both on the temperature and coupling constant g. By invoking a Principle of Minimal Sensitivity (PMS) of the path integral to the effective frequency, we derive a mathematically well-defined analytic formula for the partition function. Quite remarkably, the formula reproduces qualitatively and quantitatively the key features of the exact partition function. The free energy is accurate to a few percent over the entire range of temperatures and coupling strengths g. Both the harmonic ( g → 0 ) and classical (high-temperature) limits are exactly recovered. The divergence of the power series of the ground-state energy at weak coupling, characterized by a factorial growth of the perturbational energies, is reproduced as well as the functional form of the strong-coupling expansion along with accurate coefficients. Explicit accurate expressions for the ground- and first-excited state energies, E 0 (g) and E 1 (g) are also presented. [ABSTRACT FROM AUTHOR]

We are concerned with the following nonlinear Hartree system − Δ u + P 1 (| x |) u = α 1 | x | − 1 ∗ u 2 u + β | x | − 1 ∗ v 2 u in R 3 , − Δ v + P 2 (| x |) v = α 2 | x | − 1 ∗ v 2 v + β | x | − 1 ∗ u 2 v in R 3 , where P1(r) and P2(r) are positive radial potentials, α1 > 0, α2 > 0 and β ∈ R is a coupling constant. We first study nondegeneracy of ground states for the limit system of the above problem. As applications, we show that the nonlinear Hartree system has infinitely many non-radial positive synchronized solutions, whose energy can be arbitrarily large. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate stakeholders' perception of the most prevalent unethical practices in the Ghanaian construction industry. Design/methodology/approach: Data used for this study came from a cross-sectional survey (questionnaire), which was administered to 273 stakeholders in the construction industry using convenience sampling technique. The data were analyzed using statistical software package SPSSv17 to determine the most prevalent unethical practices. The ranking factor was calculated based on relative importance index (RII) value. Findings: The results of this study reveal that corruption was perceived by major stakeholders as the most prevalent unethical behavior (RII = 0.82) followed by bribery (RII = 0.79). Political interference and kickback came third (RII = 0.77) and fourth (RII = 0.74), respectively. However, the least prevalent unethical behaviors were extortion (RII = 0.56), workplace violence (RII = 0.57), alcohol abuse (RII = 0.59) and harassment (RII = 0.59). The findings suggest that when the various groupings were taken into consideration separately, the differences in their perceptions were obvious. Research limitations/implications: Data for this study were collected from construction stakeholders in Ghana who were conveniently sampled. As a result, in reference to the sampling framework which focused on major stakeholders in only two regions of Ghana does not sufficiently ensure full generalization of the results. Practical implications: The findings of the study provide significant information for construction organizations and practitioners regarding unethical practices, which are most prevalent in the Ghanaian construction industry. Construction organizations and practitioners seeking to mitigate the negative effect of unethical practices on their performance should focus on educating construction workers on how to avoid corrupt practices and report same to the authorities. Also, ethics training programs must be instituted for staff coupled with constant and random inspection and checking of ethical compliance, verbal promotion and praise for ethical conduct and in some cases increase in employees pay. Originality/value: This paper is one of the first to have accessed the views of broader stakeholders, i.e. consultants, contractors, professionals, suppliers, regulators, clients and construction workers in the construction industry regarding the most prevalent unethical practices in the Ghanaian construction industry in one study. This study, therefore, enriches the current literature by providing additional dimension to the understanding of unethical practices in the Ghanaian construction industry. [ABSTRACT FROM AUTHOR]

[Display omitted] In addition to the pressurized high-temperature superconductivity, bilayer and trilayer nickelate superconductors La n +1 Ni n O 3 n +1 (n = 2 and 3) exhibit many intriguing properties at ambient pressure, such as orbital-dependent electronic correlation, non-Fermi liquid behavior, and density-wave transitions. Here, using ultrafast reflectivity measurement, we observe a drastic difference between the ultrafast dynamics of the bilayer and trilayer nickelates at ambient pressure. We observe a coherent phonon mode in La 4 Ni 3 O 10 involving the collective vibration of La, Ni, and O atoms, which is absent in La 3 Ni 2 O 7. Temperature-dependent relaxation time diverges near the density-wave transition temperature of La 4 Ni 3 O 10 , while it is inversely proportional to the temperature in La 3 Ni 2 O 7 above ∼150 K, suggesting a non-Fermi liquid behavior of La 3 Ni 2 O 7. Moreover, we estimate the electron–phonon coupling constants to be 0.05–0.07 and 0.12–0.16 for La 3 Ni 2 O 7 and La 4 Ni 3 O 10 , respectively, suggesting a relatively minor role of electron–phonon coupling in the electronic properties of La n +1 Ni n O 3 n +1 at ambient pressure. The relevant microscopic interaction and dynamic information are essential for further studying the interplay between superconductivity and density-wave transitions in nickelate superconductors. [ABSTRACT FROM AUTHOR]

Structural regulation of crystal structures to achieve specific structural architectures and/or desired functionalities is one of the main focuses in the field of molecular magnetism. The reaction of a trigonal tetradentate ligand, [TpFeIII(CN)3]− bridging unit and cobalt metal centres by the altering change of chemical stoichiometry afforded three different structures [{TpFe(CN)3}2Co(PyPz3)]·4MeOH·5H2O (1), [{TpFe(CN)3}Co(PyPz3)]2(ClO4)2·2MeCN·2H2O (2) and {(Tp)Fe(CN)3Co(PyPz3)}n(BF4)n·2nMeOH (3) (PyPz3 = 2-(di(1H-pyrazol-1-yl)methyl)-6-(1H-pyrazol-1-yl)pyridine and [TpFeIII(CN)3]− = tri(pyrazolyl)boratetricyanoiron(III)). Detailed structural studies reveal a gradual transformation among the complexes, from a trinuclear structure in 1, to a tetranuclear geometry in 2, and finally to a one-dimensional chain in 3. Magnetic susceptibility measurements revealed that all three complexes exhibit ferromagnetic interactions between the cyanide bridged FeIII and CoII centres, with exchange coupling constants of +7.89, +4.37, and +5.92 cm−1, respectively. Our result demonstrates an effective strategy for targeted assembly of architectures by introducing coordinatively unsaturated ligands, complemented by the cyanide-bridged linkers [TpRFeIII(CN)3]−. [ABSTRACT FROM AUTHOR]

This paper discusses hyperconjugative stereoelectronic effects in borazines. A series of alkyl-substituted borazines were synthesized and analysed by NMR spectroscopy and X-ray diffraction. Supported by NBO analyses, the significant decreases in 1JCH coupling constant for the CH groups adjacent to the boron atoms are consistent with the presence of and interactions. These interactions lower the electrophilicity of boron atoms, enhancing moisture stability and establishing these molecules as valuable scaffolds in synthetic chemistry and materials science. [ABSTRACT FROM AUTHOR]

The constant current followed by constant voltage (CC-CV) charging method is commonly employed for battery charging, effectively extending battery life and reducing charging time. However, as charging progresses, the battery's internal resistance increases, complicating the charging circuit. This paper designs a wireless power transfer system utilizing an LCL coupling network for battery charging. The system employs frequency modulation (FM) to manage its CC and CV output characteristics at two fixed frequency points. The influence of the LCL coupling network parameters on system output characteristics was investigated using MATLAB. A simulation model was developed in the PSIM environment to validate the CC and CV output characteristics. The simulation results show that the system has load-independent constant-current and constant-voltage characteristics at two different frequency points. In order to verify the theoretical analysis, an experimental platform was also established. Experimental results demonstrate that the proposed system operates effectively in CC mode, maintaining constant output current across various loads, while in CV mode, it effectively regulates output voltage for different loads. The designed frequency modulation controller ensures a rapid response to sudden changes in load resistance, regardless of operating in CC or CV modes. [ABSTRACT FROM AUTHOR]

In this work, we investigate some extensions of the Kiselev black hole solutions in the context of f(핋,풯) gravity. By mapping the components of the Kiselev energy–momentum tensor into the anisotropic energy–momentum tensor and assuming a particular form of f(핋,풯), we obtain exact solutions for the field equations in this theory that carries dependence on the coupling constant and on the parameter of the equation of state of the fluid. We show that in this scenario of modified gravity some new structure is added to the geometry of spacetime as compared to the Kiselev black hole. We analyze the energy conditions, mass, horizons and the Hawking temperature considering particular values for the parameter of the equation of state. [ABSTRACT FROM AUTHOR]

Endohedral metallofullerenes (EMFs) are constructed by fullerene cages encapsulating various metal atoms or metal clusters, which usually exhibit some motion. However, due to the fact that the elusive endohedral dynamics are related to many factors, it remains a challenge to image the motion of internal species. Recently, the electron spin was found to be a sensitive probe to detect the motion of internal species in EMFs. Moreover, this technique can be widely applied for many metallofullerenes, i.e., for paramagnetic EMFs, the unpaired electron spin is a natural probe for the endohedral dynamics, and for diamagnetic EMFs, an electron can be introduced to produce spin-active EMF molecules. Based on the analysis of hyperfine coupling constants (hfcc), g-factors, and line patterns of the ESR spectra of EMFs, the spin centers and endohedral dynamics can be deduced. It has been revealed that the spin probes can provide unexpected information about the dynamics of the internal clusters in EMFs. Through changing the temperature, exohedral modification of the EMF, and supramolecular assembly, the motion of the internal species in EMFs can be manipulated, as clearly reflected by the spin probe. These studies revealed that the spin in EMFs exhibits promising applications in quantum sensing and molecular machine technology. In this review, we will address the use of the spin probe in EMFs and attempt to understand the effects in the detection of the endohedral dynamics. [ABSTRACT FROM AUTHOR]

The magnetic nature of nonalternant hydrocarbon (Azulene) bridged nitronyl nitroxide (AzNN2) and imino‐nitroxide (AzIN2) diradicals are investigated with 38 different DFT functionals to find out a correct functional to predict the magnetic nature of these diradicals. The effect of Hartree–Fock exchange (HFX) in the hybrid functionals are investigated for the prediction of magnetic nature of the nonalternant hydrocarbon bridged diradicals. The utility of Borden and Davidson's proposal of disjoint and nondisjoint SOMOs for the prediction of magnetic nature of alternant hydrocarbon bridged diradicals is assessed for the nonalternant hydrocarbon based diradicals. The more affordable meta‐GGA functionals was found to be outperforming the costlier hybrid and double‐hybrid functionals in predicting the magnetic properties of nonalternant hydrocarbon‐bridged diradicals. HFX significantly influences a functional's ability to predict a diradical's magnetic nature. Interestingly, Borden and Davidson's concept of disjoint and nondisjoint SOMOs, which is used to predict the magnetic behavior of alternant hydrocarbon diradicals, is reversed for nonalternant hydrocarbon‐bridged diradicals. The difference in the magnetic nature of the two diradicals come from the canonical molecular orbitals of the diradicals, one has set of disjoint SOMOs and other has nondisjoint SOMOs. [ABSTRACT FROM AUTHOR]

The discovery of ~80 K superconductivity in nickelate La3Ni2O7 under pressure has ignited intense interest. Here, we present a comprehensive first-principles study of the electron-phonon (e-ph) coupling in La3Ni2O7 and its implications on the observed superconductivity. Our results conclude that the e-ph coupling is too weak (with a coupling constant λ ≲ 0.5) to account for the high Tc, albeit interesting many-electron correlation effects exist. While Coulomb interactions (via GW self-energy and Hubbard U) enhance the e-ph coupling strength, electron doping (oxygen vacancies) introduces no major changes. Additionally, different structural phases display varying characteristics near the Fermi level, but do not alter the conclusion. The e-ph coupling landscape of La3Ni2O7 is intrinsically different from that of infinite-layer nickelates. These findings suggest that a phonon-mediated mechanism is unlikely to be responsible for the observed superconductivity in La3Ni2O7, pointing instead to an unconventional nature. [ABSTRACT FROM AUTHOR]

In this paper, we study the dynamical stability analysis by considering the torsion field ϕ which is proportional to the Hubble parameter and barotropic equation-of-state parameter in the framework of the homogenous and isotropic FLRW metric with non-zero torsion in the scenario of dark matter and dark energy interacting terms. We discuss the stability of the critical points corresponding to the eigenvalues in the presence of dust and radiation at quintessence, Λ CDM and phantom regimes by utilizing the different linear and nonlinear interaction models which depend on the energy density. As a result, we observe that the first linear model shows the stable behavior throughout the universe for dust and radiation phase. The other linear and nonlinear models show the stable critical points, computing with the eigenvalues at phantom and Λ CDM era with the best fit value of interaction strength and coupling constant for dust and radiation. [ABSTRACT FROM AUTHOR]

Let H 0 be the free Dirac operator and V ⩾ 0 be a positive potential. We study the discrete spectrum of H (α) = H 0 - α V in the interval (- 1 , 1) for large values of the coupling constant α > 0 . In particular, we obtain an asymptotic formula for the number of eigenvalues of H (α) situated in a bounded interval [ λ , μ) as α → ∞ . [ABSTRACT FROM AUTHOR]

Cathinone and its synthetic derivatives belong to organic compounds with narcotic properties. Their structural diversity and massive illegal use create the need to develop new analytical methods for their identification in different matrices. NMR spectroscopy is one of the most versatile methods for identifying the structure of organic substances. However, its use could sometimes be very difficult and time-consuming due to the complexity of NMR spectra, as well as the technical limitations of measurements. In such cases, molecular modeling serves as a good supporting technique for interpreting ambiguous spectral data. Theoretical prediction of NMR spectra includes calculation of nuclear magnetic shieldings and sometimes also indirect spin–spin coupling constants (SSCC). The quality of theoretical prediction is strongly dependent on the choice of the theory level. In the current study, cathinone and its 12 fluorinated derivatives were selected for gauge-including atomic orbital (GIAO) NMR calculations using Hartree–Fock (HF) and 28 density functionals combined with 6-311++G** basis set to find the optimal level of theory for 1H, 13C, and 19F chemical shifts modeling. All calculations were performed in the gas phase, and solutions were modeled with a polarized-continuum model (PCM) and solvation model based on density (SMD). The results were critically compared with available experimental data. [ABSTRACT FROM AUTHOR]

The quantitative solution conformations of 2‐(hydroxymethyl)‐tetrahydropyran, α‐methyl‐d‐mannopyranoside, and 6‐[α‐d‐mannopyranosyl]‐d‐mannopyranose (mannobiose) are described. Parametrized Karplus equations for redundant spin pairs across the terminal ω‐torsion and the glycosidic ω‐torsion for mannobiose are developed, including ω/θ‐hypersurfaces for the terminal hydroxymethylene group. Experimental NMR data, algorithmic spectral simulation (clustered Hamiltonian method), molecular dynamics (MD) simulations (GLYCAM06), energy minimizations by DFT, and adjusted torsion angle populations weighted over the Karplus‐type equations are used. We demonstrate that spectral simulation is a powerful tool in the refinement of initial J values obtained from static GAIO DFT calculations. We also show that only as few as one of multiple redundant torsions can be diagnostic for conformational analysis of the disaccharide. [ABSTRACT FROM AUTHOR]

In this paper we study Einstein-bumblebee gravity theory minimally coupled with external matter – a phantom/non-phantom (conventional) scalar field, and derive a series of hairy solutions – bumblebee-phantom (BP) and BP-dS/AdS black hole solutions, regular Ellis-bumblebee-phantom (EBP) and BP-AdS wormholes, etc. We first find that the Lorentz violation (LV) effect can change the so-called black hole no-hair theorem and these scalar fields can give a hair to a black hole. If LV coupling constant ℓ > - 1 , the phantom field is admissible and the conventional scalar field is forbidden; if ℓ < - 1 , the phantom field is forbidden and the conventional scalar field is admissible. By defining the Killing potential ω ab , we study the Smarr formula and the first law for the BP black hole, find that the appearance of LV can improve the structure of these phantom hairy black holes – the conventional Smarr formula and the first law of black hole thermodynamics still hold; but for no LV case, i.e., the regular phantom black hole reported in (Phys Rev Lett 96:251101), the first law cannot be constructed at all. We also show there still exists a stable circular orbit around the BP black hole. When the bumblebee potential is linear, we find that the phantom potential and the Lagrange-multiplier λ behave as a cosmological constant Λ . [ABSTRACT FROM AUTHOR]

In this work, we investigate the effect of curved spacetime on neutrino oscillation. In a curved spacetime, the effect of curvature on fermionic fields is represented by spin connection. The spin connection consists of a non-universal "contorsion" part which is expressed in terms of vector and axial current density of fermions. The contraction of contorsion part with the tetrad fields, which connects the internal flat space metric and the spacetime metric, is called torsion. In a scenario where neutrino travels through background of fermionic matter at ordinary densities in a curved spacetime, the Hamiltonian of neutrino oscillation gets modified by the torsional coupling constants λ 21 ′ and λ 31 ′ . The aim of this work is to study the effect of λ 21 ′ and λ 31 ′ in DUNE and P2SO. In our study we, (i) discuss the effect of torsional coupling constants on the neutrino oscillation probabilities, (ii) estimate the capability of P2SO and DUNE to put bounds on these parameters and (iii) show how the physics sensitivities get modified in presence of torsion. [ABSTRACT FROM AUTHOR]

A measurement of the dijet production cross section is reported based on proton–proton collision data collected in 2016 at s = 13 Te V by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of up to 36.3 fb - 1 . Jets are reconstructed with the anti- k T algorithm for distance parameters of R = 0.4 and 0.8. Cross sections are measured double-differentially (2D) as a function of the largest absolute rapidity | y | max of the two jets with the highest transverse momenta p T and their invariant mass m 1 , 2 , and triple-differentially (3D) as a function of the rapidity separation y ∗ , the total boost y b , and either m 1 , 2 or the average p T of the two jets. The cross sections are unfolded to correct for detector effects and are compared with fixed-order calculations derived at next-to-next-to-leading order in perturbative quantum chromodynamics. The impact of the measurements on the parton distribution functions and the strong coupling constant at the mass of the Z boson is investigated, yielding a value of α S (m Z) = 0.1179 ± 0.0019 . [ABSTRACT FROM AUTHOR]

The scattering of H by I is a prototypical model system for light-heavy scattering in which relativistic coupling effects must be taken into account. Scattering calculations depend strongly on the accuracy of the potential energy surface (PES) model. The methodology to obtain such an accurate PES model suitable for scattering calculations is presented, which includes spin–orbit (SO) coupling within the Effective Relativistic Coupling by Asymptotic Representation (ERCAR) approach. In this approach, the SO coupling is determined only for the atomic states of the heavy atom, and the geometry dependence of the SO effect is accounted for by a diabatization with respect to asymptotic states. The accuracy of the full model, composed of a Coulomb part and the SO model, is achieved in the following ways. For the SO model, the extended ERCAR approach is applied, which accounts for both intra-state and inter-state SO coupling, and an extended number of diabatic states are included. The corresponding coupling constants for the SO operator are obtained from experiments, which are more accurate than computed values. In the Coulomb Hamiltonian model, special attention is paid to the long range behavior and accurate c6 dispersion coefficients. The flexibility and accuracy of this Coulomb model are achieved by combining partial models for three different regions. These are merged via artificial neural networks, which also refine the model further. In this way, an extremely accurate PES model for hydrogen iodide is obtained, suitable for accurate scattering calculations. [ABSTRACT FROM AUTHOR]

Quantum-chemical calculations aimed at deriving magnetic coupling constants in exchange-coupled spin clusters commonly utilize a broken-symmetry (BS) approach. This involves calculating several distinct collinear spin configurations, predominantly by density-functional theory. The energies of these configurations are interpreted in terms of the Heisenberg model, H ̃ = ∑ i < j J i j s ̃ i ⋅ s ̃ j , to determine coupling constants Jij for spin pairs. However, this energy-based procedure has inherent limitations, primarily in its inability to provide information on isotropic spin interactions beyond those included in the Heisenberg model. Biquadratic exchange or multi-center terms, for example, are usually inaccessible and hence assumed to be negligible. The present work introduces a novel approach employing BS mean-field solutions, specifically Hartree–Fock wave functions, for the construction of effective spin Hamiltonians. This expanded method facilitates the extraction of a broader range of coupling parameters by considering not only the energies, but also Hamiltonian and overlap elements between different BS states. We demonstrate how comprehensive s = 1 2 Hamiltonians, including multi-center terms, can be straightforwardly constructed from a complete set of BS solutions. The approach is exemplified for small clusters within the context of the half-filled single-band Hubbard model. This allows to contrast the current strategy against exact results, thereby offering an enriched understanding of the spin-Hamiltonian construction from BS solutions. [ABSTRACT FROM AUTHOR]

Reliable prediction of the ground-state spin and magnetic coupling constants in transition-metal complexes is a well-known challenge for density functional theory (DFT). One popular strategy for addressing this long-standing issue involves the modification of the fraction of Fock exchange in a hybrid functional. Here we explore the viability of this approach using three polynuclear metal-organic complexes based on a Ni4O4 cubane motif, having different ground state spin values (S = 0, 2, 4) owing to the use of different ligands. We systematically search for an optimum fraction of Fock exchange, across various global, range-separated, and double hybrid functionals. We find that for all functionals tested, at best there only exists a very narrow range of Fock exchange fractions which results in a correct prediction of the ground-state spin for all three complexes. The useful range is functional dependent, but general trends can be identified. Typically, at least two similar systems must be used in order to determine both an upper and lower limit of the optimal range. This is likely owing to conflicting demands of minimizing delocalization errors, which typically requires a higher percentage of Fock exchange, and addressing static correlation, which typically requires a lower one. Furthermore, we find that within the optimal range of Fock exchange, the sign and relative magnitude of Ni–Ni magnetic coupling constants are reasonably well reproduced, but there is still room for quantitative improvement in the prediction. Thus, the prediction of spin state and magnetic coupling in polynuclear complexes remains an ongoing challenge for DFT. [ABSTRACT FROM AUTHOR]

A positive Mu is a useful tool for investigating the spin density of radical species. The theoretical estimation of its behavior in a molecule requires the inclusion of a quantum effect due to the small mass of muonium. Herein, we performed ab initio a path integral molecular dynamics (PIMD) simulation, which accurately included a multi-dimensional quantum effect, for muoniated 9H-xanthene-9-thione (μXT). Our results showed that the quantum effect significantly increased the hyperfine coupling constant (HFCC) value of μXT, which qualitatively improved the calculated HFCC value, compared to the experimental one. In the PIMD simulation, the bond length between muonium and sulfur in μXT is longer than that between hydrogen and sulfur in a hydrogenated 9H-xanthene-9-thione (HXT), leading to a spin density transfer from XT (9H-xanthene-9-thione) to muonium due to neutral dissociations. Additionally, we found that the S–Mu bond in μXT prefers a structure perpendicular to the molecular plane, where the interaction between Mu and the singly occupied molecular orbital of μXT is the strongest. These structural changes resulted in a larger HFCC value in the PIMD simulation of μXT. [ABSTRACT FROM AUTHOR]

Despite the fact that most quantum chemistry basis sets are designed for accurately modeling valence chemistry, these general-purpose basis sets continue to be widely used to model core-dependent properties. Core-specialized basis sets are designed with specific features to accurately represent the behavior of the core region. This design typically incorporates Gaussian primitives with higher exponents to capture core behavior effectively, as well as some decontraction of basis functions to provide flexibility in describing the core electronic wave function. The highest Gaussian exponent and the degree of contraction for both s- and p-basis functions effectively characterize these design aspects. In this study, we compare the design and performance of general-purpose basis sets against several literature-based basis sets specifically designed for three core-dependent properties: J coupling constants, hyperfine coupling constants, and magnetic shielding constants (used for calculating chemical shifts). Our findings consistently demonstrate a significant reduction in error when employing core-specialized basis sets, often at a marginal increase in computational cost compared to the popular 6-31G** basis set. Notably, for expedient calculations of J coupling, hyperfine coupling, and magnetic shielding constants, we recommend the use of the pcJ-1, EPR-II, and pcSseg-1 basis sets, respectively. For higher accuracy, the pcJ-2, EPR-III, and pcSseg-2 basis sets are recommended. [ABSTRACT FROM AUTHOR]

This paper proposes an elastic topological resonator derived from the Kekulé tight-binding model, which enables the quantum spin Hall effect (QSHE). Band inversion in the spin system is realized through fine-tuning the intracellular coupling constants. With full-wave simulations, the topological interface configurations demonstrate the robust spin-locked edge state transport characteristic, featuring excellent fidelity via defects and anti-direct transmission. Then, a hexagonal resonator is located beside the straight waveguide to achieve multiple effective coupling directed by the edge state. The effect of the distance between the straight waveguide and the hexagonal part is further analyzed on the number of the resonant mode. Based on the functionally graded design concept, the topological resonance rainbow is also proposed to spatially separate distinct frequency components in accordance with projected band branches, to realize the progressive propagation of Lamb waves along the resonator route. Our work provides a novel mechanism for manipulating elastic waves with topological edge states, which is anticipated to serve as a foundation for creating programmable sensors and multifunctional testing equipment. [ABSTRACT FROM AUTHOR]

In this paper, we study an effective field theory (EFT) for a singlet scalar extension of the standard model (SM). The tree- and one-loop level effective actions are derived by integrating out the heavy singlet scalar in the Lagrangian for the UV theory and by applying to the functional method, respectively. In the UV model, the light scalar field identified with the SM Higgs is assumed to be massless in the symmetric phase. When the heavy singlet scalar acquires a vacuum expectation value, the Z 2 symmetry is broken and a mass term of the light scalar is induced. In light of EFT we derive, the electroweak vacuum resulting in 126 GeV Higgs mass can be attained when the induced squared-mass term of the light scalar in the scalar potential becomes negative. This condition can occur when the constant of the scalar coupling between the two different scalars is allowed to be negative. We investigate how the EFT can be constrained by theory and experiments. We also examine whether or not electroweak phase transition (EWPT) in this scenario can be a first order. Some numerical results leading to the first-order EWPT while satisfying the constraints studied are presented. [ABSTRACT FROM AUTHOR]

The μ‐phenoxido‐bridged dinuclear copper(II) complex, [Cu2(L1)2(dmso)(MeOH)] (1), has been synthesized using N′‐(4‐(diethylamino)‐2‐hydroxybenzylidene)‐1‐naphthohydrazide (H2L1) as ligand. The structural analysis of 1 reveals that the coordination geometry at the copper ions is best described as a square pyramidal with a Cu⋅⋅⋅Cu distance in the dinuclear complex of 303 pm which is supported by hydrogen bonding between the two apical oxygen donor ligands (O⋅⋅⋅O 277 pm). Magnetic studies indicate that 1 exhibits a strong antiferromagnetic interaction between the two copper(II) ions with a coupling constant of J=−450 cm−1 (H^=-JS^1S^2 ${\widehat{{\rm H}}=-J{\widehat{{\rm S}}}_{1}{\widehat{{\rm S}}}_{2}}$). The magnetic exchange is transmitted through the central [Cu2(OR)2]2+ core, a fragment for which different magneto‐structural correlations have been reported depending on the substituent at the bridging oxygen atom. However, the properties of complex 1 cannot be explained by any of the established correlations. Nevertheless, complex 1, together with the series of compounds based on an acylhydrazone ligand framework reported so far, shows a magneto‐structural correlation as a function of the Cu−O−Cu bridging angle that significantly differs from all previously reported. [ABSTRACT FROM AUTHOR]