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Molecular structures and adsorption of dyes on bismuth oxychloride surfaces using density functional theory and Monte Carlo dynamic simulation

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Results in physics 2025年 68卷

作者： Wakjira, Tadesse Lemma Gemta, Abebe Belay Tadele, Kumneger Kassahun, Gashaw Beyene sherefedin, Umer Gurumurthi, T. Feyisa, Tesfaye Department of Applied Physics School of Applied Natural Sciences Adama Science and Technology University P.O. Box Adama 1888 Ethiopia Department of Physics College of Natural and Computational Sciences Haramaya University P.O. Box 138 Dire Dawa Ethiopia

The adsorption behavior of different dyes (methylene blue (MB), methyl orange (MO) and methyl red (MR)) on the BiOCl surface was investigated through density functional theory calculations and Monte Carlo dynamic simulations. The results indicate that the majority of electrons within the dye molecules are involved primarily in bonding interactions, which contributes to a stable electronic configuration in aqueous environment. Moreover, the calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the dyes demonstrated that they have distinct electronic characteristics, with respective values of HOMO approximately −4.25, −5.70, and −5.53 eV respectively, whereas their corresponding LUMO levels were −4.25, −5.70, and −5.53 eV, respectively. Quantum theory of atoms in molecules analysis shows three critical points (atom, bond and ring) were observed in each dye. The 2D-reduced density gradient graph and 3D isosurfaces of the non-covalent interaction analysis for the three dye confirms repulsive, attractive and weak interactions. Furthermore, the molecular electrostatic potential map analysis of the dyes revealed regions of varying potential values indicating both nucleophilic and electrophilic sites. A stronger affinity of MO for the surface was observed, with a adsorption energy of −89.34 kcal/mol, compared with −70.82 and −60.55 for MB and MR, respectively. These findings underscore the potential of BiOCl not only as a superior photocatalyst but also as an efficient sorbent for dye removal in wastewater treatment applications. © 2024 The Author(s)

关键词： Adsorption BiOCl Dyes Molecular structure

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Diverse Manifestations of Electron-Phonon Coupling in a Kagome Superconductor

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Physical Review Letters 2025年第10期134卷 106401-106401页

作者： Jing-Yang You Chih-En Hsu Mauro Del Ben Zhenglu Li Mork Family Department of Chemical Engineering and Materials Science University of Southern California Los Angeles California 90089 USA Department of Physics National University of Singapore 2 Science Drive 3 Singapore 117551 Singapore Department of Physics Tamkang University Tamsui New Taipei 251301 Taiwan Applied Mathematics and Computational Research Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA

Recent angle-resolved photoemission spectroscopy (ARPES) experiments on the kagome metal CsV3Sb5 revealed distinct multimodal dispersion kinks and nodeless superconducting gaps across multiple electron bands. The prominent photoemission kinks suggest a definitive coupling between electrons and certain collective modes, yet the precise nature of this interaction and its connection to superconductivity remain to be established. Here, employing the state-of-the-art ab initio many-body perturbation theory computation, we present direct evidence that electron-phonon (e-ph) coupling induces the multimodal photoemission kinks in CsV3Sb5, and profoundly, drives the nodeless s-wave superconductivity, showcasing the diverse manifestations of the e-ph coupling. Our calculations well capture the experimentally measured kinks and their fine structures, and reveal that vibrations from different atomic species dictate the multimodal behavior. Results from anisotropic GW-Eliashberg equations predict a phonon-mediated superconductivity with nodeless s-wave gaps, in excellent agreement with various ARPES and scanning tunneling spectroscopy measurements. Despite the universal origin of the e-ph coupling, the contributions of several characteristic phonon vibrations vary in different phenomena, highlighting a versatile role of e-ph coupling in shaping the low-energy excitations of kagome metals.

关键词： Shear waves

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Approximating reproduction numbers: a general numerical method for age-structured models

arXiv

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arXiv 2023年

作者： De Reggi, Simone Scarabel, Francesca Vermiglio, Rossana CDLAb - Computational Dynamics Laboratory University of Udine Italy Department of Mathematics Computer Science and Physics University of Udine Italy Department of Applied Mathematics University of Leeds United Kingdom

In this paper, we introduce a general numerical method to approximate the reproduction numbers of a large class of multi-group, age-structured, population models with a finite age span. To provide complete flexibility in the definition of the birth and transition processes, we propose an equivalent formulation for the age-integrated state within the extended space framework. Then, we discretize the birth and transition operators via pseudospectral collocation. We discuss applications to epidemic models with continuous and piecewise continuous rates, with different interpretations of the age variable (e.g., demographic age, infection age and disease age) and the transmission terms (e.g., horizontal and vertical transmission). The tests illustrate that the method can compute different reproduction numbers, including the basic and type reproduction numbers as special *** Codes 34L16, 37N25, 65L15, 65L60, 65P99, 92D25, 92D30 Copyright © 2023, The Authors. All rights reserved.

关键词： Numerical methods

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Photodissociation dynamics of SiH+: Rovibrationally resolved Feshbach resonances mediated by coupled excited states in the ultraviolet region

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Physical Review A 2025年第1期111卷 013118-013118页

作者： Yu Kun Yang Xing Guang Su Kun Wang Yongjun Cheng Quan Wei Nan Zeqing Wang Danny L. Yeager Yong Wu Jian Guo Wang School of Physics Henan Normal University Xinxiang 453000 China Institute of Environmental Science Shanxi University Taiyuan 030006 China School of Physics and Information Technology Shaanxi Normal University Xi'an 710119 China Department of Physics Renmin University of China Beijing 100872 China Department of Chemistry Texas A&M University College Station Texas 77843 USA Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China

Photodissociation cross sections of SiH+ have been explored within the uncoupled theoretical framework, notably in the work of Stancil et al. [Astrophys. J. 486, 574 (1997)]. However, in the SiH+ system, there are significant nonadiabatic interactions between the 31Π and 41Π states, which substantially affect the photodissociation process, particularly in the region between the Lyman α line and the Lyman limit. These nonadiabatic couplings give rise to numerous Feshbach resonances, significantly altering the final photodissociation cross sections. The present study highlights the critical importance of incorporating nonadiabatic electronic couplings to achieve accurate cross-section calculations. The results substantially enrich the data set on small molecular structures and spectra in interstellar clouds, providing essential theoretical support for future experimental investigations and for the modeling and analysis of stellar spectra. Additionally, this work offers key insights into the underlying physical mechanisms by which Feshbach resonances modulate line shapes in coupled photodissociation scattering cross sections.

关键词： Photodissociation

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Nature of spin-lattice coupling in two-dimensional CrI_(3) and CrGeTe_(3)

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science China(physics,Mechanics & Astronomy) 2021年第8期64卷 63-71页

作者： Jing Li JunSheng Feng PanShuo Wang ErJun Kan HongJun Xiang Key Laboratory of Computational Physical Sciences(Ministry of Education) State Key Laboratory of Surface Physicsand Department of PhysicsFudan UniversityShanghai 200433China Shanghai Qi Zhi Institute Shanghai 200232China School of Physics and Materials Engineering Hefei Normal UniversityHefei 230601China Department of Applied Physics and Institution of Energy and Microstructure Nanjing University of Science and TechnologyNanjing 210094China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Spin-lattice (SL) coupling plays an important role in spintronic applications given its effects on magnetic,ferroelectric,optical,and thermodynamic *** and theoretical calculations have revealed a large SL coupling effect in CrGeTe_(3) and CrI_(3) ***,the microscopic origin of SL coupling in these systems is still *** this work,we develop a systematic method to explore the atomistic mechanism of SL coupling based on the density functional *** find that the first-and second-order SL couplings in ternary system CrGeTe_(3) are considerably stronger than those in binary system CrI_(3).For the first-order SL coupling,the Cr ions of the magnetic pair and Ge ions positively contribute to the strain enhancement of ferromagnetism in CrGeTe_(3).However,the Cr ions provide a negative contribution in CrI_(3).Furthermore,our tight-binding analysis suggests that the p-d hopping in CrGeTe_(3) gradually decreases with the tensile strain,rapidly enhancing the ferromagnetism under the tensile *** large frequency shifts in CrGeTe_(3) are caused by the large second-order exchange derivatives (one type of second-order SL coupling) of the Cr ions of the magnetic pair.

关键词： spin-lattice effect two-dimensional magnetic materials first-principle calculation

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Account of non-standard orbits in computations of neoclassical toroidal viscous torque in the resonant plateau regime of a tokamak

Account of non-standard orbits in computations of neoclassic...

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2022 Joint Varenna-Lausanne International Workshop on the Theory of Fusion Plasmas, Varenna-Lausanne 2022

作者： Buchholz, R. Kasilov, S.V. Kernbichler, W. Grabenwarter, L. Savchenko, A.A. Albert, C.G. Fusion@ÖAW Institut für Theoretische Physik - Computational Physics Technische Universität Graz Petersgasse 16 GrazA-8010 Austria Institute of Plasma Physics National Science Center Kharkov Institute of Physics and Technology Kharkiv61108 Ukraine Department of Applied Physics and Plasma Physics V. N. Karazin Kharkov National University Kharkiv61022 Ukraine

This article extends theoretical details based on a short paper originally submitted to the 2022 EPS conference in plasma physics [1]. The quasilinear theory of resonant transport regimes in a tokamak is developed for the general case of orbits forming various classes separated in phase space by homoclinic orbits with infinite bounce time. Beyond standard orbits (banana and passing orbits) also all types of non-standard orbits (e.g. "potato"orbits) are taken into account. In case of a weak radial electric field, such orbits are usually present only near the magnetic axis. If the radial electric field cannot be treated as weak, there can be arbitrary many classes, located elsewhere. The present approach covers all such cases and is demonstrated on a specific example of a radial electric field profile. The resulting quasilinear kinetic equation is applicable to compute neoclassical toroidal viscous (NTV) torque in a tokamak with non-axisymmetric magnetic field perturbations. A fully non-local approach to NTV computation has been realized in the upgraded version of the code NEO-RT. Based on a generalization of magnetic flux surfaces to drift surfaces, the notion of a local thermodynamic equilibrium is extended for our purpose. We obtain an expression for the integral toroidal torque within a chosen flux surface and dicuss means to compute such integrals taking singularities in bounce and precession frequencies into account. © Published under licence by IOP Publishing Ltd.

关键词： Integral equations

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A Pseudo-Spectral Scheme for Systems of Two-Point Boundary Value Problems with Left and Right Sided Fractional Derivatives and Related Integral Equations

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Computer Modeling in Engineering & sciences 2021年第7期128卷 21-41页

作者： I.G.Ameen N.A.Elkot M.A.Zaky A.S.Hendy E.H.Doha Department of Mathematics Faculty of ScienceAl-Azhar UniversityCairoEgypt Department of Mathematics Faculty of ScienceCairo UniversityGiza12613Egypt Department of Applied Mathematics Physics DivisionNational Research CentreDokkiCairo12622Egypt Department of Computational Mathematics and Computer Science Institute of Natural Sciences and MathematicsUral Federal UniversityYekaterinburg620002Russia Department of Mathematics Faculty of ScienceBenha UniversityBenha13511Egypt

We target here to solve numerically a class of nonlinear fractional two-point boundary value problems involving left-and right-sided fractional *** main ingredient of the proposed method is to recast the problem into an equivalent system of weakly singular integral ***,a Legendre-based spectral collocation method is developed for solving the transformed ***,we can make good use of the advantages of the Gauss quadrature *** present the construction and analysis of the collocation *** results can be indirectly applied to solve fractional optimal control problems by considering the corresponding Euler–Lagrange *** numerical examples are given to confirm the convergence analysis and robustness of the scheme.

关键词： Spectral collocation method weakly singular integral equations two-point boundary value problems convergence analysis

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The lower moments of nucleon structure functions in lattice QCD with physical quark masses 38

The lower moments of nucleon structure functions in lattice ...

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38th International Symposium on Lattice Field Theory, LATTICE 2021

作者： Tsuji, Ryutaro Aoki, Yasumichi Ishikawa, Ken-Ichi Kuramashi, Yoshinobu Sasaki, Shoichi Shintani, Eigo Yamazaki, Takeshi Department of Physics Tohoku University Sendai980-8578 Japan RIKEN Center for Computational Science Kobe650-0047 Japan Core of Research for the Energetic Universe Graduate School of Advanced Science and Engineering Higashi-Hiroshima739-8526 Japan Center for Computational Sciences University of Tsukuba Tsukuba305-8577 Japan Faculty of pure and Applied Sciences University of Tsukuba Tsukuba305-8571 Japan Present adress is RIKEN Center for Computational Science Kobe650-0047 Japan

We present results for the nucleon structure functions and form factors obtained from 2+1 flavor lattice QCD with physical light quark masses (mπ = 135 MeV) in a large spatial extent of about 10 fm. Our calculations are performed with the PACS10 gauge configurations generated by the PACS Collaboration with the six stout-smeared O(a) improved Wilson-clover quark action and Iwasaki gauge action at β = 1.82 and 2.00 corresponding to lattice spacings of 0.085 fm and 0.064 fm respectively. The lower moments of structure functions, hxiu−d and hxi∆u−∆d given by the twist-2 operators being properly renormalized, are evaluated in the MS scheme at the renormalization scale of 2 GeV only at β = 1.82, since the renormalization factors at β = 2.00 have not yet determined nonperturbatively in the RI/MOM scheme. Instead, at two lattice spacings, we evaluate appropriate ratios of gA/gV and hxiu−d/hxi∆u−∆d, which are not renormalized in the continuum limit. These quantities thus can be directly compared with the experimental data without the renormalization. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)

关键词： Gages

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Chirality-selective transparency induced by lattice resonance in bilayer metasurfaces

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Photonics Research 2021年第4期9卷 484-493页

作者： Shuxia Zhao Lei Shao Jianfang Wang Hai-Qing Lin Wei Zhang Institute of Applied Physics and Computational Mathematics Beijing 100088China Beijing Computational Science Research Center Beijing 100193China Department of Physics The Chinese University of Hong KongShatinHong Kong SARChina

Chiral optical responses of bilayer metasurfaces made of twisted metallic nanorods are investigated in detail with focus on the collective effect due to lattice resonance(LR).Using an analytical approach based on the coupled dipole method(supported by full wave simulation),we find optical chirality is dramatically increased by the coupling between localized surface plasmon resonances and *** collective effect results in significant chiral signal even for metasurfaces made of achiral unit *** interlayer coupling generally destroys the Wood’s anomaly and the associated *** making use of Pancharatnam–Berry(PB)phase and propagation phase,one can modulate the optical activity effectively and achieve chirality-selective transparency induced by LR in a designed structure with a g-factor of absorption as high as 1.99(close to the upper limit of 2).Our studies not only reveal a new mechanism of modulating chiral optical response by combination effects from PB phase,propagation phase,and LR,but also give a quantitative relationship between the geometry configuration and chiral optical properties,thus providing helpful guidance for device design.

关键词： transparency chiral lattice

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Iterative approach to linear ideal MHD modeling of plasma response to 3D magnetic perturbations in tokamaks

Iterative approach to linear ideal MHD modeling of plasma re...

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2022 Joint Varenna-Lausanne International Workshop on the Theory of Fusion Plasmas, Varenna-Lausanne 2022

作者： Lainer, P. Kasilov, S.V. Kernbichler, W. Reichelt, M. Albert, C.G. Fusion@ÖAW Institute of Theoretical and Computational Physics Graz University of Technology Petersgasse 16 Graz8010 Austria Institute of Plasma Physics National Science Center Kharkov Institute of Physics and Technology Kharkiv61108 Ukraine Department of Applied Physics and Plasma Physics V. N. Karazin Kharkov National University Svobody sq. 4 Kharkiv61022 Ukraine

The class of plasma instabilities known as edge-localized modes (ELMs) is of special concern in tokamaks operating in high-confinement mode, such as ASDEX Upgrade and ITER. One strategy for ELM mitigation is the application of resonant magnetic perturbations (RMPs) via external coils. Kinetic modeling accurately describes the plasma response to these RMPs ab initio, particularly the parallel shielding currents at resonant surfaces. Away from resonant surfaces, ideal magnetohydrodynamics (iMHD) is expected to yield sufficiently accurate results, providing a computationally less expensive option that could complement kinetic modeling. The code MEPHIT has been developed to solve the linearized iMHD equations in a way that is compatible with iterative kinetic modeling approaches. We consider an axisymmetric iMHD equilibrium in realistic tokamak geometry under the influence of a quasi-static non-axisymmetric external perturbation from ELM mitigation coils. The plasma responds to this external magnetic perturbation with a current perturbation, which in turn produces a magnetic field perturbation. The resulting fixed-point equation can be solved in a self-consistent manner by preconditioned iterations in which Ampère's equation and the magnetic differential equations for pressure and current are solved in alternation until convergence is reached. After expansion in toroidal Fourier harmonics, these equations are solved on a triangular mesh in the poloidal plane using finite elements. These results are then benchmarked against established codes. © Published under licence by IOP Publishing Ltd.

关键词： Magnetoplasma

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