An energy minimization formulation of electrostatics that allows computation of the electrostatic energy and forces to any desired accuracy in a system with arbitrary dielectric properties is presented. An integral equation for the scalar charge density is derived from an energy functional of the polarization vector field. This energy functional represents the true energy of the system even in nonequilibrium states. Arbitrary accuracy is achieved by solving the integral equation for the charge density via a series expansion in terms of the equation's kernel, which depends only on the geometry of the dielectrics. The streamlined formalism operates with volume charge distributions only, not resorting to introducing surface charges by hand. Therefore, it can be applied to any spatial variation of the dielectric susceptibility, which is of particular importance in applications to biomolecular systems. The simplicity of application of the formalism to real problems is shown with analytical and numerical examples.
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http://dx.doi.org/10.1103/PhysRevE.79.041907 | DOI Listing |
J Phys Chem B
January 2025
School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Hydration free energy (HFE) of molecules is a fundamental property having importance throughout chemistry and biology. Calculation of the HFE can be challenging and expensive with classical molecular dynamics simulation-based approaches. Machine learning (ML) models are increasingly being used to predict HFE.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Institute of Physical Chemistry, RWTH Aachen University, Aachen 52074, Germany.
Exploring the conformational space of molecules remains a challenge of fundamental importance to quantum chemistry: identification of relevant conformers at ambient conditions enables predictive simulations of almost arbitrary properties. Here, we propose a novel approach, called TTConf, to enable conformational sampling of large organic molecules where the combinatorial explosion of possible conformers prevents the use of a brute-force systematic conformer search. We employ tensor trains as a highly efficient dimensionality reduction algorithm, effectively reducing the scaling from exponential to polynomial.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, Leuven, 3001, Belgium.
The next generation of soft electronics will expand to the third dimension. This will require the integration of mechanically compliant 3D functional structures with stretchable materials. Here, omnidirectional direct ink writing (DIW) of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) aerogels with tunable electrical and mechanical performance is demonstrated, which can be integrated with soft substrates.
View Article and Find Full Text PDFThe elimination of the A' unit from -type Y6-derivatives has led to the development of a new class of -benzodipyrrole (-BDP)-based A-DBD-A-type NFAs. In this work, two new A-DBD-A-type NFAs, denoted as CFB and CMB, are designed and synthesized, where electron-withdrawing fluorine atoms and electron-donating methyl groups are substituted on the benzene ring of the -BDP moiety, respectively. CFB exhibits a blue-shifted absorption spectrum, stronger intermolecular interactions, shorter π-π stacking distances, and more ordered 3D intermolecular packing in the neat and blend films, enabling it to effectively suppress charge recombination in the PM6:CFB device showing a higher PCE of 16.
View Article and Find Full Text PDFFront Neurosci
January 2025
School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan City, China.
Introduction: Transcranial magnetic stimulation (TMS) is widely used for the noninvasive activation of neurons in the human brain. It utilizes a pulsed magnetic field to induce electric pulses that act on the central nervous system, altering the membrane potential of nerve cells in the cerebral cortex to treat certain mental diseases. However, the effectiveness of TMS can be compromised by significant heat generation and the clicking noise produced by the pulse in the TMS coil.
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