Article
Nanoscience & Nanotechnology
Weilin Liu, Euan Mcleod
Summary: Metasurface design is often tedious and time-consuming due to the variation of geometric parameters. This paper proposes a method based on the discrete dipole approximation (DDA) to reduce simulation time and compares its accuracy and speed with the finite difference time domain (FDTD) method. The results show that the 1D cylindrical approach performs best, providing fast and accurate simulations.
Article
Chemistry, Physical
Christian S. Ahart, Kevin M. Rosso, Jochen Blumberger
Summary: Constrained density functional theory (CDFT) is a powerful tool for predicting electron transfer parameters in condensed phase simulations. In this study, an extension to CDFT is presented in the popular electronic structure package CP2K, implementing additional force terms based on Hirshfeld charge partitioning. The improved method shows good agreement with previous results at a lower computational cost, and the general reliability of condensed phase CDFT calculations is discussed.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Biochemistry & Molecular Biology
Nicholas J. Fowler, Marym F. Albalwi, Subin Lee, Andrea M. Hounslow, Mike P. Williamson
Summary: Using the program ANSURR, we found that protein structures calculated from NMR data are less accurate and defined due to a lack of hydrogen bond restraints. We developed a protocol to introduce hydrogen bond restraints systematically and transparently in the structure calculation of the SH2 domain from SH2B1, resulting in improved accuracy and definition of the generated structures. We also demonstrate that ANSURR can serve as a guide to determine when to stop the structure calculation.
Article
Multidisciplinary Sciences
Filipa R. Prudencio, Mario G. Silveirinha
Summary: Photonic topological materials with broken time-reversal symmetry exhibit nontrivial topological phases, supporting edge-state propagation when enclosed by specific boundaries. The Haldane model revealed the importance of broken time-reversal symmetry for quantized electronic Hall phase. In photonics, the Haldane model's magnetic field can be mimicked using a spatially varying pseudo-Tellegen coupling, leading to nontrivial phase transitions controlled by the amplitude of the pseudo-Tellegen parameter in photonic crystals.
Article
Energy & Fuels
Xiangyu Meng, Jianguo Sun, Puli Wei, Yangyang Xu, Zeshuang Xu
Summary: A biaxial parabolic approximation method is proposed for enlarging the angle domain in which the parabolic approximation to the acoustic wave equation is applied, allowing for efficient handling of strong velocity contrast in the horizontal direction while maintaining a good balance between efficiency and accuracy.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Soham Chattopadhyay, Dallas R. Trinkle
Summary: In this study, we extend the Green's function approach to accurately compute transport coefficients for interstitial dumbbell-mediated mechanisms in dilute limit for arbitrary crystalline systems with non-truncated correlations. We also present and compare results of tracer correlation factors, solute drag ratios, and partial diffusion coefficient ratios in iron and nickel-based alloys, discussing some aspects of correlated solute-dumbbell motion.
PHILOSOPHICAL MAGAZINE
(2022)
Article
Computer Science, Interdisciplinary Applications
Xu He, Nicole Helbig, Matthieu J. Verstraete, Eric Bousquet
Summary: TB2J is a Python package for the automatic computation of magnetic interactions in magnetic crystals based on density functional calculations. It requires only one first-principles electronic structure calculation in the non-relativistic case, and can be directly used for adiabatic magnon band structure and spin dynamics calculations. Its main advantage lies in its minimal user input requirement and easy integration into high-throughput workflows.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Computer Science, Interdisciplinary Applications
Julee Shahni, Randhir Singh
Summary: This paper proposes an efficient numerical technique based on the Bernstein polynomials for the numerical solution of the derivative dependent Emden-Fowler boundary value problems. By converting the integral equation into a system of nonlinear equations using the Bernstein collocation method and solving it efficiently with a suitable iterative method, accurate numerical solutions are obtained. The method is analyzed for error and compared with other known techniques.
ENGINEERING WITH COMPUTERS
(2022)
Article
Engineering, Electrical & Electronic
Ioan E. Lager, Martin Stumpf, Guy A. E. Vandenbosch, Giulio Antonini
Summary: This paper critically revisits the late-time evaluation of electromagnetic field quantities using convolution integrals. It traces the causes of divergent late-time behavior and proposes a framework that combines integral partitioning and polynomial approximation to guarantee convergence. Numerical experiments validate the accuracy and computational efficiency of the method, making it applicable to a wide range of problems requiring late-time evaluation of convolution integrals.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Yihua Dan, Zhanlong Zhang, Hui Zhao, Yiqiao Li, Huarui Ye, Jun Deng
Summary: A new segmented sampling numerical calculation method (SSNCM) is proposed for grounding parameters in horizontally layered soils. This method shows better calculation efficiency and adaptability for different layered soils, providing a theoretical foundation for grounding parameters analysis and grounding devices design.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2021)
Article
Mathematics, Applied
A. L. Balandin
Summary: The paper focuses on the electromagnetic inverse scattering problem for dielectric anisotropic and magnetically isotropic media. It introduces the tensor Fourier diffraction theorem as a useful tool for studying tensor fields in inverse electromagnetic scattering problems.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2024)
Article
Physics, Multidisciplinary
Yi-Qian Sun, T. J. Gao
Summary: This paper investigates the influence of electron interaction on the magnetic coupling between diluted magnetic semiconductor quantum dots embedded in semiconductors. The RKKY magnetic interaction between the local spins of two diluted magnetic semiconductor quantum dots in the semiconductor is calculated using the Keldysh Green's function method, considering the electronic interaction using a simple self-consistent mean-field approximation.
INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS
(2021)
Article
Chemistry, Physical
Sandor Guba, Barnabas Horvath, Istvan Szalai
Summary: According to various theoretical models, the heating performance of magnetic fluids under alternating magnetic field is proportional to the imaginary part of the complex susceptibility. However, the magnetic field strength dependence of the susceptibility is often only considered by the Langevin theory. In this study, a theoretical model based on the mean spherical approximation theory and including dipole-dipole interactions was proposed to calculate the magnetic properties and derive the power dissipation. The predictions were verified by experimental data, showing that the commonly used Langevin limiting case underestimates the power dissipation.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Nanoscience & Nanotechnology
Hyunjun Ma, Jin-Soo Kim, Jong-Ho Choe, Q-Han Park
Summary: We propose a metasurface antenna capable of real-time holographic beam steering by reconfigurable dipoles. We use a deep learning algorithm that combines an autoencoder with an electromagnetic scattering equation to determine the states required for a target far-field pattern in real-time. Our learning-based algorithm requires a computing time of within 200 mu s to determine the meta-atomic states, enabling the real-time operation of a holographic antenna.
Article
Engineering, Electrical & Electronic
Philippe De Tillieux, Yves Goussard
Summary: Magnetic induction tomography is a novel imaging method with promising biomedical applications, but suffers from high computation cost in image reconstruction. This study proposes a numerical model based on inhomogeneous Green's function, reducing the number of unknowns and computation cost.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Chemistry, Physical
Kushantha P. K. Withanage, Kamal Sharkas, J. Karl Johnson, John P. Perdew, Juan E. Peralta, Koblar A. Jackson
Summary: This study reveals that density functional theory-based descriptions may lead to overestimation of adsorption energies, but the errors can be significantly reduced by introducing self-interaction corrections.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Prakash Mishra, Yoh Yamamoto, Po-Hao Chang, Duyen B. Nguyen, Juan E. Peralta, Tunna Baruah, Rajendra R. Zope
Summary: This study examines the impact of reducing self-interaction correction on the evaluation of magnetic exchange coupling constants. The results show that the local scaling method performs better than other methods for complex organic systems and chlorocuprates, indicating the importance of self-interaction correction in accurately predicting magnetic exchange couplings.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Dian-Teng Chen, Phillip Helms, Ashlyn R. Hale, Minseong Lee, Chenghan Li, Johnnie Gray, George Christou, Vivien S. Zapf, Garnet Kin-Lic Chan, Hai-Ping Cheng
Summary: The researchers studied the high-nuclearity single-molecule magnet Mn-84 through theoretical calculation and experimental measurement. They derived the exchange interactions between different spins in the magnet using first-principles calculations, and computed the exact partition function of observables such as heat capacity and magnetization through quantum simulation techniques. The results showed qualitative agreement between theory and experiment, and identified limitations in current theoretical modeling of large magnets.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Inorganic & Nuclear
Ashlyn R. Hale, Megan E. Lott, Juan E. Peralta, Dolos Foguet-Albiol, Khalil A. Abboud, George Christou
Summary: This article reports on the synthesis, structure, and magnetic properties of three related iron(III)-oxo clusters. The study reveals that all the complexes exhibit dominant antiferromagnetic coupling, and the ground-state spins of the molecules were determined through calculations and a magnetostructural correlation.
INORGANIC CHEMISTRY
(2022)
Article
Physics, Condensed Matter
V Petkov, J. E. Peralta, B. Aoun, Y. Ren
Summary: In this study, the complex charge density wave (CDW) phases of layered 1T-TaS2 were explored using x-ray pair distribution function (PDF) analysis and computer modeling. The structure models obtained capture the atomic-level features and can be used for electronic structure calculations. The results confirm the presence of star-of-David (SD) like clusters of Ta atoms in the high-temperature incommensurate (IC) CDW phase and show that the low-temperature commensurate (C) CDW phase expands upon cooling, reducing lattice strain. Furthermore, the C-CDW phase maintains the stacking sequence of Ta-S layers observed in the room temperature, nearly commensurate (NC) CDW phase. The DFT calculations based on the PDF refined model indicate that bulk C-CDW 1T-TaS2 retains the insulating state of individual layers of SD clusters, supporting the Mott physics description of the metal-to-insulator (NC-CDW to C-CDW) phase transition in 1T-TaS2. This work emphasizes the importance of precise crystal structure models in determining the electronic phases of complex materials.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Multidisciplinary Sciences
Sudipto Chakrabarti, Ayelet Vilan, Gai Deutch, Annabelle Oz, Oded Hod, Juan E. Peralta, Oren Tal
Summary: When reducing materials to the nanoscale, magnetic properties can emerge due to structural variations. This study demonstrates the reverse effect, where the structure of nanomaterials is controlled by magnetic manipulations. The results show that the applied magnetic field direction affects the interatomic distance and length of nanowires, suggesting that magnetic fields can control the atomistic structure of different nanomaterials during their formation.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Isaiah A. Moses, Veronica Barone, Juan E. Peralta
Summary: This work focuses on using crystalline materials databases and machine learning models to explore the chemical space of materials for energy storage applications. By screening inorganic materials from existing databases, the researchers built a new database of electrode materials and developed an efficient protocol for data mining and screening. The expanded battery dataset was then used to build deep neural network models that accurately predict average voltages and percentage volume changes upon charging and discharging.
JOURNAL OF POWER SOURCES
(2022)
Article
Chemistry, Inorganic & Nuclear
Ashlyn R. Hale, Lucas E. Aebersold, Juan E. Peralta, Dolos Foguet-Albiol, Khalil A. Abboud, George Christou
Summary: The synthesis, structure, and magnetic properties of [Fe7O3((O2CBu)-Bu-t)(9)(mda)(3)(H2O)(3)] (1) are reported. The ground state spin and exchange parameters of the compound were determined using experimental and theoretical methods, and the frustration effects of spin were explained.
Article
Chemistry, Physical
Juan I. Melo, Mark R. Pederson, Juan E. Peralta
Summary: The FLOSIC method effectively removes the self-interaction error in the Perdew-Zunger framework by using localized Fermi-Lo''wdin orbitals. A detailed workflow for the implementation of the FLOSIC method in DFT calculations is provided, which takes advantage of the unitary invariant nature of the method. The algorithm's convergence characteristics are analyzed and applications for calculating NMR shielding constants and real-time time-dependent DFT simulations are presented.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Inorganic & Nuclear
Ashlyn R. Hale, Khalil A. Abboud, George Christou
Summary: New members of the Mn70 and Mn84 torus-like cluster family have been prepared by reacting [Mn12O12(O2CR)16(H2O)4] with R ' CO2H and NBuMnO4 or MnII salts. It has been concluded that the determination of Mn70 vs Mn84 nuclearity depends on the relative bulk of carboxylates vs alkoxides, with larger carboxylates favoring Mn84. The newly synthesized clusters 3-5 exhibit frequency-dependent x ''m signals below approximately 2.4 K, indicating that they are new members of the giant [Mn14] torus family of giant single-molecule magnets (SMMs), with Mn84 and Mn70 being the largest homometallic Mn/O clusters and SMMs to date.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Annabelle Oz, Abraham Nitzan, Oded Hod, Juan E. Peralta
Summary: This study introduces a first-principles approach to describe electron dynamics in open quantum systems. By using time-dependent density functional theory on finite model systems and imposing open boundary conditions via the driven Liouville-von Neumann methodology, the analysis of non-equilibrium dynamics is achieved.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Juan I. Melo, Mark R. Pederson, Juan E. Peralta
Summary: The study presents a detailed workflow for the implementation of the FLOSIC method in DFT calculations to remove self-interaction error. The method utilizes the unitary invariant nature to perform self-consistent energy minimization, similar to standard Kohn-Sham with the PZ self-interaction correction. The algorithm includes iterations for density matrix and fermi-lowdin descriptors and provides expressions for effective Kohn-Sham matrix and FOD gradients suitable for electronic structure codes. Convergence characteristics are analyzed, and applications for NMR shielding constants and real-time time-dependent DFT simulations are presented.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)