Static Moment Research Articles

Gravelly soil uniformity identification based on the optimized Mask R-CNN model

The uniformity of gravelly soil has an important influence on compaction quality. The most important task to judge the uniformity of gravelly soil is to segment the gravels from the image. However, gravels are widely and densely distributed, and their particle size varies greatly, increasing segmentation difficulty. Among existing studies, research on rapid and quantitative judgment methods of gravelly soil uniformity remains scarce. To address the abovementioned issue, a gravelly soil uniformity identification based on the optimized Mask R-CNN model is proposed. The original Mask R-CNN only produces one combined mask of multiple overlapping gravels, which hinders postprocessing and uniformity calculation. To address this problem, separate masks for each gravel are generated for better parameter calculation. Then, according to the characteristics of the pixel image of a single mask, the calculation of static moment is deduced and simplified. Finally, the single mask dataset of the optimized Mask R-CNN and static distance theory are used to establish a quantitative evaluation index of gravelly soil uniformity, in which the uniformity coefficient (UC) and area ratio coefficient (ARC) are adopted. In addition, the convergence curves and the Average Precision (AP) of the ResNet101 and the ResNet50 backbones are compared, and the result proves the superiority of ResNet101 in gravel segmentation. Furthermore, three data enhancement methods (namely, rotation, mirroring, and brightness transformation) are adopted to improve the AP performance and result in a 2.32% increase. The application in a real large-scale hydropower project shows that the AP can reach 88.96%, and each calculation and analysis can be controlled within one minute, which shows the effectiveness, convenience and efficiency of the method.

Two-step Mott transition in Ni(S,Se)2 : μSR studies and charge-spin percolation model

A pyrite system ${\mathrm{NiS}}_{2\ensuremath{-}x}{\mathrm{Se}}_{x}$ exhibits a bandwidth controlled Mott transition via (S,Se) substitutions in a two-step process: the antiferromagnetic insulator (AFI) to antiferromagnetic metal (AFM) transition at $x\ensuremath{\sim}0.45$ followed by the AFM to paramagnetic metal (PMM) transition at $x\ensuremath{\sim}1.0$. Among a few other Mott systems which exhibit similar two-step transitions, $\mathrm{Ni}{(\mathrm{S},\mathrm{Se})}_{2}$ is of particular interest because a large intermediate AFM region in the phase diagram would provide unique opportunities to study the interplay between the spin and charge order. Muon spin relaxation ($\ensuremath{\mu}\mathrm{SR}$) measurements on ${\mathrm{NiS}}_{2\ensuremath{-}x}{\mathrm{Se}}_{x}$ have been carried out on seven different Se concentrations from $x=0$ to 1.0. The results on quantum evolution demonstrate significantly random spin correlations in the AFM region associated with a rapid reduction of the average local static Ni moment size with increasing $x$, yet without signatures of macroscopic phase separation as confirmed by nearly full volume fraction participating in the static muon relaxation process up to $x\ensuremath{\sim}$ 0.9 at low temperatures. The observed time spectra in the AFM region indicate Lorentzian distribution of static internal field expected for a spatially dilute spin structure. No signature of dynamic critical behavior was observed in thermal phase transitions. The previous neutron scattering studies found sharp magnetic Bragg peaks with a slower reduction of the average ordered moment size in the AFM region. By comparing and combining the muon and neutron results, here we propose a picture where the spin order is maintained by the percolation of ``nonmetallic'' localized and dangling Ni moments surrounded by S, while the charge transition from AFI to AFM is caused by the percolation of the conducting paths generated by the Ni-Se-Ni bonds. This model of interpenetrating charge and spin percolation captures the behavior of experimental results on (a) Se concentration for the insulator to metal transition, (b) Se concentration for the AFM to PMM transition, (c) variation of Hall effect in the AFM region due to conducting Ni charges on the backbone of the percolating charge network, (d) evolution of the neutron Bragg intensity, (e) evolution of the muon static local fields, and (f) spatial variation of the local conductance observed by STM.

Design, Synthesis, DFT, TD-DFT/PCM Calculations, and Molecular Docking Studies on the Anti-COVID-19, and Anti-SARS Activities of Some New Bis-Thiazoles and Bis-Thiadiazole

A novel synthesis of bis(thiazoles) and bis(thiadiazole), each connected to a thienothiophene moiety, is described. The DFT calculations support the favored synthesis of one of the anticipated bis(thiazole) regioisomers. The B3LYP/6-311G** level of theory was used to optimize quantum mechanical calculations of geometrical characteristics and energy of new compounds under study. The electronic absorption of the new compounds in ethanol solvent was handled and finished using time-dependent-density functional theory (TD-DFT) at the B3LYP/6-31G(d,p) level with the addition of the polarizable continuum solvation technique TD-DFT/PCM. The permissible singlet transitions are identified, and their involvements in the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) are described. Natural bond orbital (NBO) analysis was used to investigate hyper conjugative partnerships, molecular stability, and bond strength. Mean polarizability, total static dipole moment, anisotropy of polarizability, and mean first-order hyperpolarizability have all been computed. The results reveal that the compounds are promising contenders for non-linear optical materials. The molecular docking mechanism between ligands 8a–8c and COVID-19/5epw or SARS/5wrg receptors was done to explore the binding modes of these compounds at the active sites. Molecular docking results have shown that the compounds 8a–8c can be considered as a potential agent against COVID-19/5epw and SARS/5wrg receptors.

Sensitivity of Internal Tibial Forces and Moments to Static Optimization Moment Constraints at the Subtalar and Ankle Joints.

We examined the sensitivity of internal tibial forces and moments during running to different subtalar/ankle moment constraints in a static optimization routine. Seventeen participants ran at 2.20, 3.33, and 4.17 ms-1 while force and motion data were collected. Ankle joint contact force was estimated using inverse-dynamics-based static optimization. Three sets of joint moment constraints were tested. All sets included the flexion-extension and abduction-adduction moments at the hip and the flexion-extension moment at the knee but differed in the constraints used at the subtalar/ankle: (1) flexion-extension at the ankle (Sag), (2) flexion-extension and inversion-eversion at ankle (Sag + Front), and (3) flexion-extension at the ankle and supination-pronation at the subtalar (Sag + SubT). Internal tibial forces and moments were quantified at the distal one-third of the tibia, by ensuring static equilibrium with applied forces and moments. No interaction was observed between running speed and constraint for internal tibial forces or moments. Sag + SubT resulted in larger internal mediolateral force (+41%), frontal (+79%), and transverse (+29%) plane moments, compared to Sag and Sag + Front. Internal axial force was greatest in Sag + Front, compared to Sag and Sag + SubT (+37%). Faster running speeds resulted in greater internal tibial forces and moments in all directions (≥+6%). Internal tibial forces and moments at the distal one-third of the tibia were sensitive to the subtalar and ankle joint moment constraints used in the static optimization routine, independent of running speed.

Prediction of anatomically and biomechanically feasible precision grip posture of the human hand based on minimization of muscle effort

We developed a method to estimate a biomechanically feasible precision grip posture of the human hand for a given object based on a minimization of the muscle effort. The hand musculoskeletal model was constructed as a chain of 21 rigid links with 37 intrinsic and extrinsic muscles. To grasp an object, the static force and moment equilibrium condition of the object, force balance between the muscle and fingertip forces, and static frictional conditions must be satisfied. We calculated the hand posture, fingertip forces, and muscle activation signals for a given object to minimize the square sum of the muscle activations while satisfying the above kinetic constraints using an evolutionary optimization technique. To evaluate the estimated hand posture and fingertip forces, a wireless fingertip force-sensing device with two six-axis load cells was developed. When grasping the object, the fingertip forces and hand posture were experimentally measured to compare with the corresponding estimated values. The estimated hand postures and fingertip forces were in reasonable agreement to the corresponding measured data, indicating that the proposed hand posture estimation method based on the minimization of muscle effort is effective for the virtual ergonomic assessment of a handheld product.

Experimental Study on Existing RC Circular Members Under Unequal Lateral Impact Train Collision

With the fast growth of high-speed rail in recent years, derailment has become the first hidden danger of high-speed rail transportation. The high-speed train passes near the station building. So the train may derail and hit the station building. Building a high-speed railway station usually uses a reinforced concrete structure. As a result of high impact energy on the impact body, the reinforced concrete (RC) member may fail; the impact point is near the member's foot; the structural member's constraint can be considered fixed support. This paper investigates the dynamic behavior of four types of circular reinforced concrete members under unequal lateral impact loads. The RC member's failure mechanism and dynamic response addressed the significance of unequal lateral impact load. The usual circular reinforced concrete members are used as the model to perform the drop-weight impact test. The specimens' crack pattern, failure mechanism, impact, deflection, and strain time–history curves are obtained. Findings show that between the impact point and the adjacent support, shear fractures occur that fail in shear mode. Shear cracks are based on impact velocity, longitudinal reinforcement ratio, and stirrup ratio. One type is more destructive to members and nodes. A shear fracture occurs when a longitudinal reinforcement fractures towards the closer support. The effects of impact velocity, longitudinal reinforcement ratio, and stirrup ratio on the dynamic impact response are studied. The experimental results may help improve structural member impact resistance. The critical section (right side) computed the static shear resistance using shear force, whereas the maximum external load resistance determines static bending moment resistance. Understanding how circular members fail to be subjected to unequal lateral impact loads provides insight into circular RC members' impact design and damage evaluation.

Application of Computer 3D Modeling Technology in Graphic Image Design.

In order to solve the problem that the manual input data work efficiency is low and the optimization cannot be achieved in the section modulus calculation, the author proposes a computer-aided 3D graphic design method for ship hull structure. First, complete the modeling of the ship hull, complete the statistical calculation of the size in the CAD platform, solve the static moment, and complete the three-dimensional modeling; Calculate the inertial load and wave load of the ship during work, and calculate the wave bending moment, and substitute it into the three-dimensional model for verification. Finally, according to the computer-aided three-dimensional graphic design process, the specification verification of the ship's scale is completed, the graphic file is associated with the database, and the three-dimensional graphic design is completed. Experimental results show that the maximum stress of the original three-dimensional integrated graphic design of the ship is 202 MPa, and the maximum deformation is 87.352 mm. Based on the computer-aided three-dimensional integrated graphic design of the ship, the maximum stress is 226 MPa, and the maximum deformation is 76.234 mm. In conclusion: the hull obtained by the computer-aided three-dimensional graphic design of the ship can effectively reduce the total area and materials of the midsection structure of the ship, reduce the weight of the hull, and realize the optimal configuration of the midsection material of the ship.

Laser cooling and electronic structure of Be halide anions BeX- (X = Cl, Br, F, and I).

The adiabatic potential energy curves of the low lying electronic states of the Be halide anions BeX- (Cl, Br, F, and I) have been investigated in the representation 2s+1Λ(+/-) by using the complete active space self-consistent field with a multireference configuration interaction method. The spectroscopic parameters Te, Re, ωe, and Be and the static and transition dipole moment μe were studied, and a rovibrational study of the investigated electronic states was performed. New electronic states were investigated here for the first time. The calculated highly diagonal Franck-Condon factor and the short radiative lifetime among the lowest vibrational levels of the X1Σ0+ - (1)3Π1 transitions of the molecular anion BeF- prove its candidacy for Doppler laser cooling. The experimental proof of the stability and the calculated experimental parameters, such as the vibrational branching ratio, the slowing distance, the recoil, and Doppler temperatures with the experimental conditions of the buffer gas cell of this anion, open the route for experimental work on the BeF- molecular ion.

Energy-Based Approach: Analysis of a Laterally Loaded Pile in Multi-Layered Non-Linear Elastic Soil Strata

Several studies have been reported in published literature on analytical solutions for a laterally loaded pile installed in a homogeneous single soil layer. However, piles are rarely installed in an ideal homogeneous single soil layer. The present study describes a new continuum-based analysis or energy-based approach for predicting the pile displacement responses subjected to static lateral loads and moments considering the soil non-linearity. This analytical analysis treats the pile as an elastic Euler–Bernoulli beam and the soil as a three-dimensional (3D) continuum in which the non-linear elastic properties are described by a modulus degradation relationship. The principle of virtual work was applied to the energy equation of a pile–soil system in order to obtain the governing differential equation for the pile and soil displacements. An iterative procedure was adopted to solve the equations numerically using a finite difference method (FDM). The pile displacement response was obtained using the software MATLAB R2021a, and the results from the energy-based method were compared with those obtained from the field test data as well as the finite element analysis (FEA) based on the software ANSYS Workbench 2021R1. The present study investigated the effect of explicit incorporation of soil properties and layering through a parametric study in order to understand the importance of predicting appropriate pile displacement responses in a linear elastic soil system. The responses indicated that the effect of soil layers and their thicknesses, pile properties and the variation in soil moduli have a direct impact on the displacements of piles subjected to lateral loading. Hence, a proper emphasis has to be given to account for the soil non-linearity. Considering the effect of soil non-linearity, it is observed that the results obtained from the energy-based method agreed well with the field measured values and those obtained from the FEA. The results indicated a difference of approximately less than 7% between the proposed method and the FEA. The approach presented in this study can be further extended to piles embedded in multi-layered soil strata subjected to the combined action of axial loads, lateral loads and moments. Furthermore, the same approach can be extended to study the response of the soil to group piles.

A Steroidal Molecular Rotor with Fast Solid‐State Dynamics Obtained by Crystal Engineering: Role of the Polarity of the Stator

AbstractA set of Steroidal Molecular Rotors (SMRs) were synthesized and characterized employing a Sonogashira cross‐coupling reaction as the key synthetic step. The static dipole moment (μ0) of the stator was examined as a crystal engineering criterium that could determine the easiness with which the rotator participates in the high energy supramolecular interactions that frequently preclude rotation in this class of molecular machines. The strategy is critically evaluated through theoretical/experimental analyses, featuring SXRD experiments and QM/MM computations of the rotational activation energy (Ea), allowing us to propose, within the systems studied, a potential correlation between the use of stators with lower μ0and a lowering of theEavalue. Results from solid‐state NMR revealed that one of the most promising compounds indeed hosts fast rotational motion (above 25–30 kHz), standing as a rare example of a SMR with fast rotation within a crowded crystallographic environment.

Strain energy form coefficients for bending of short beams having full and thin-walled arbitrary cross section with application for FEM and Airfoils

The aim of this work is to develop a new generalized formula and a numerical computation program for evaluating the energy form coefficient of a complex and arbitrary cross section for full and thin-walled cross section with respect to any central axis, for the bending of beams of small lengths in comparison with the transverse dimension of the section. This coefficient plays a very important role in the calculation of the deformation energy of beams subjected to bending under the effect of a shearing force for short beams. It also enters in the formulation of FEM bending model, in order to calculate the stresses and the strains due to the external forces. The application is made for complex sections used in various fields of construction and in particular for airfoils designed for aerospace construction. A method is developed to calculate this coefficient as a function of the rotation of the central axes. The calculation of the area, the moments, and the product of inertias with respect to the central axes is necessary. The formula for calculating this coefficient is presented as a definite integral of a non-analytical function determined point by point along the direction of the application of the shear force. This function is based on the calculation of the partial static moments. The calculation of the latter is based on the development of a technique by subdividing the upper part of the section into adjacent common triangles at one point for the full solid section or by segments on the boundary for the thin-walled section. To speed up the process of numerically calculating this integral with high precision and reduced time, Gauss Legendre quadrature of order 40 is used. The calculation of the distribution of the tangential stress as well as its maximum value is determined. A shear shape coefficient is therefore determined. In the second part of this work, an application is made for the static calculation by the FEM of a hyper static beam with a view to determining the influence of this coefficient on all the parameters of resistance and bending stiffness as a correction of the classical model of bending by the FEM. A study of the error made by the classical bending model on our shear effect model is presented. A coefficient of efficiency of a section is presented.

Laser Cooling with an Intermediate State and Electronic Structure Studies of the Molecules CaCs and CaNa.

The ground and excited electronic states of the diatomic molecules CaCs and CaNa have been investigated by implementing the ab initio CASSCF/(MRCI + Q) calculation. The potential energy curves of the doublet and quartet electronic low energy states in the representation 2s+1Λ(±) have been determined for the two considered molecules, in addition to the spectroscopic constants Te, ωe, Be, Re, and the values of the dipole moment μe and the dissociation energy De. The determination of vibrational constants Ev, Bv, Dv, and the turning points Rmin and Rmax up to the vibrational level v = 100 was possible with the use of the canonical functions schemes. Additionally, the transition and the static dipole moments curves, Einstein coefficients, the spontaneous radiative lifetime, the emission oscillator strength, and the Franck–Condon factors are computed. These calculations showed that the molecule CaCs is a good candidate for Doppler laser cooling with an intermediate state. A “four laser” cooling scheme is presented, along with the values of Doppler limit temperature TD = 55.9 μK and the recoil temperature Tr = 132 nK. These results should provide a good reference for experimental spectroscopic and ultra-cold molecular physics studies.

STUDY OF EQUIPMENT FOR CONDUCTING SOIL COMPACTIONS FOR SMALL CONSTRUCTION OBJECTS

Compaction of soils of different composition is widely used in all types of construction. To carry out these works, the domestic industry produces various types of machinery and equipment. The range of these tools is constantly expanding. Their capacity is also growing and their working bodies are improving. Under these conditions, the issue of increasing productivity, and quality of work is very important, which is possible only with the right choice of general structural schemes of machines and their parameters. One of the important parameters of the compaction process is the time factor or the ability to change the effect of vibration on the treated medium. Increasing the time of exposure of the working equipment to the material to be compacted, or the intensity of the action improves the conditions of formation of the structure of the rolling layer, and its greatest strength is achieved. When performing work on private plots of small area, compact road equipment, such as a mini-roller, has found wide application in the process of soil compaction, which involves work in a limited space. This paper proposes the design of such a technique, which is equipped with a mechanism for smooth change of force that excites vibration. To perform soil compaction operations for small objects, we have proposed to use an advanced manual vibrating roller with a step change of static torque and autonomous power supply from the battery, which is connected to the drive through the inventory. The change of static moment occurs due to the change of the angle of inclination from the centre of unbalance to the axis of rotation of the shaft. If it is necessary to arrange the foundations for laying various road and decorative coatings in individual construction, a vibrating roller is used, which not only has a compact design, but also does not require mandatory wide-amplitude manoeuvres for high-quality compaction of the material. Changing the static torque of the operator while driving allows you to quickly adjust to different types of soil, and battery operation allows you to stay out of power for a while, which gives an additional advantage, especially important when working on remote construction sites.

Structural, thermal, linear and nonlinear optical and cytotoxicity studies of a novel organic stilbazolium salt: 4-[2-(4-hydroxyphenyl)ethenyl]-1-methylpyridinium 4-styrenesulfonate

Organic non-linear single crystals of 4-[2-(4-hydroxyphenyl)ethenyl]-1-methylpyridinium 4-styrenesulfonate (HMSS) are grown by means of slow solvent evaporation growth process. Stoichiometric ratio of the elements existing in the compound is identified by elemental analysis. Single crystal X-ray diffraction discloses that the developed crystal being included in to P21/n space group with monoclinic crystal system. In addition, an analysis of crystal structure and Hirshfeld surface are used to expose the intermolecular interaction and hydrogen bonds. Quantum chemical calculations performed using the density functional theory (DFT) at DFT/B3LYP/6–311+G(d,p) level of the compound provides further insight on the properties in particular molecular electrostatic potential, natural bonding orbital analysis (NBO), Mulliken and NPA charges, static dipole moment, polarizability, first order hyperpolarizability and thermodynamic functions. The frequencies (vibrational) of the compound HMSS are recognized using FT-IR and FT-Raman analysis and compared with the calculated data. Thermal properties of HMSS are accomplished via the way of TG and DSC analyses. Further, antiproliferative behavior of the obtained compound is assayed against human breast adenocarcinoma cells MCF 7 and normal Vero cells (monkey's kidney cells).

Spectroscopic and electric properties of the TaO[formula omitted] molecule ion for the search of new physics: A platform for identification and state control

The TaO+ cation is an attractive molecular species to search for parity- and time-reversal-violating interactions, in particular of hadronic origin. For the spectroscopic detection and preparation of TaO+ cation in a desired state detailed knowledge of spectroscopic and electric properties in excited states is essential information. In this work we present spectroscopy constants for TaO+ in the electronic ground and 29 excited states calculated with relativistic configuration interaction theory. The equilibrium bond lengths (Re), harmonic vibrational frequencies (ωe), transition dipole moments (TDM), vertical excitation energies and static molecular dipole moments (PDM) are summarized. We include a detailed characterization of all electronic states in terms of their spinor occupations. This work supports the realization of experiments using TaO+ ions to search for new physics beyond the standard model of elementary particles.

Optical absorption of interlayer excitons in transition-metal dichalcogenide heterostructures.

Interlayer excitons, electron-hole pairs bound across two monolayer van der Waals semiconductors, offer promising electrical tunability and localizability. Because such excitons display weak electron-hole overlap, most studies have examined only the lowest-energy excitons through photoluminescence. We directly measured the dielectric response of interlayer excitons, which we accessed using their static electric dipole moment. We thereby determined an intrinsic radiative lifetime of 0.40 nanoseconds for the lowest direct-gap interlayer exciton in a tungsten diselenide/molybdenum diselenide heterostructure. We found that differences in electric field and twist angle induced trends in exciton transition strengths and energies, which could be related to wave function overlap, moiré confinement, and atomic reconstruction. Through comparison with photoluminescence spectra, this study identifies a momentum-indirect emission mechanism. Characterization of the absorption is key for applications relying on light-matter interactions.

Self-consistent assessments for the effective properties of two-phase composites within strain gradient elasticity

Analytical method for the second-order homogenization of two-phase composites within Mindlin–Toupin strain gradient elasticity theory is proposed. Direct approach and self-consistent approximation are used to reduce the homogenization problem to the problem of determination of averaged Cauchy stresses, double stresses and static moments of Cauchy stresses inside the inclusions under prescribed quadratic boundary conditions. The ellipsoidal shape of inclusions and orthotropic properties of phases are assumed. Extended equivalent inclusion method with linear eigenstrain is proposed to derive the explicit relations between the Eshelby-like tensors and corresponding concentration tensors that are used to define the averaged field variables inside the inclusions. Obtained analytical solutions allow to evaluate the effective classical and gradient elastic moduli of composite materials accounting for the phases properties, volume fraction, shape and size of inclusions. Presented solution for the effective gradient moduli covers the full range of volume fraction and correctly predicts the absence of gradient effects for the homogeneous classical Cauchy medium. Examples of calculations for the composites with spherical inclusions are given. Micro-scale definition of the well-known simplified strain gradient elasticity theory is provided. Namely, it is shown that this theory is the phenomenological continuum model for the composites with isotropic matrix and with the small volume fraction of stiff isotropic spherical inclusions, which have the same Poisson’s ratio to those one of matrix phase.

Laser cooling and electronic structure studies of BaI molecule

Literature shows a lack of laser cooling studies of Barium Monohalide (BaI) diatomic molecules. In this work, we present a series of calculations using the ab initio complete active space self-consistent field (CASSCF)/MRCI approach with Davidson correction to fill out this gap. The adiabatic potential energy curves, the static dipole moment curves, and the spectroscopic parameters have been investigated for the bound low-lying electronic states. The ro-vibrational constants Ev, Bv, Dv, and the turning points Rmin and Rmax were also examined for the surveyed electronic states. The calculation of the transition dipole moment curves for the X2Σ+- (1)2Π transition, the Franck-Condon factor, the radiative lifetime, the branching ratio, the laser cooling scheme, and the buffer gas study prove that the molecule BaI is a good candidate for a Doppler laser cooling experiment.

Electronic structure and magnetism of the Hund's insulator CrI3

${\mathrm{CrI}}_{3}$ is a two-dimensional ferromagnetic (FM) van der Waals material with a charge gap of 1.1--1.2 eV. In this paper, the electronic structure and magnetism of ${\mathrm{CrI}}_{3}$ are investigated by using density functional theory and dynamical mean-field theory. Our calculations successfully reproduce a charge gap of $\ensuremath{\sim}1.1\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ in the paramagnetic (PM) state when a Hund's coupling ${J}_{\mathrm{H}}=0.7\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ is included with an onsite Hubbard $U=5\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$. In contrast, with a large $U$ value of 8 eV and negligible Hund's coupling ${J}_{\mathrm{H}}, {\mathrm{CrI}}_{3}$ is predicted to be a moderately correlated metal in the PM state. We conclude that ${\mathrm{CrI}}_{3}$ is a Mott-Hund's insulator due to the half-filled configuration of the Cr $3d {t}_{2g}$ orbitals. The Cr $3d {e}_{g}$ orbitals are occupied by $\ensuremath{\sim}1$ electron, which leads to strong valence fluctuations so that the Cr $3d$ orbitals cannot be described by a single state. Moreover, at finite temperature, the calculated ordered static magnetic moment in the FM state is significantly larger in the $R\overline{3}$ phase than in the $C2/m$ phase. This observation indicates that the structural phase transition from the $C2/m$ phase to the $R\overline{3}$ phase with decreasing temperature is driven by FM spin fluctuations.

Static electric dipole moment of the francium atom induced by axionlike particle exchange

The francium atom is considered as a prospective candidate system to search for the T,P-violating electron electric dipole moment [T. Aoki et al Quantum Sci. Technol. 6, 044008 (2021)]. We demonstrate that the same experiment can be used for axionlike particles (ALP) search. For this, we calculate electronic structure constants of ALP-mediated interaction for a wide range of ALP masses. Using the recently updated constraints on the ALP-electron and ALP-nucleon coupling constants, we show that the contribution of considered interactions corresponding to these constraints can give significant contribution to atomic electric dipole moment. Therefore, obtainment of stronger restrictions for ALP characteristics in the francium atom electric dipole moment experiment is possible.