Simulations and experiments are reported for nonequilibrium steady-state assembly of small colloidal crystal clusters in rotating magnetic fields vs frequency and amplitude. High-dimensional trajectories of particle coordinates from image analysis of experiments and from Stokesian Dynamic computer simulations are fit to low-dimensional reaction coordinate based Fokker-Planck and Langevin equations. The coefficients of these equations are effective energy and diffusivity landscapes that capture configuration-dependent energy and friction for nonequilibrium steady-state dynamics. Two reaction coordinates that capture condensation and anisotropy of dipolar chains folding into crystals are sufficient to capture high-dimensional experimental and simulated dynamics in terms of first passage time distributions. Our findings illustrate how field-mediated nonequilibrium steady-state colloidal assembly dynamics can be modeled to interpret and design pathways toward target microstructures and morphologies.
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http://dx.doi.org/10.1063/1.5094554 | DOI Listing |
Photochem Photobiol
December 2024
Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil.
Given that non-equilibrium molecular motion in thermal gradients is influenced by both solute and solvent, the application of spectroscopic methods that probe each component in a binary mixture can provide insights into the molecular mechanisms of thermal diffusion for a large class of systems. In the present work, we use an all-optical setup whereby near-infrared excitation of the solvent leads to a steady-state thermal gradient in solution, followed by characterization of the non-equilibrium system with electronic spectroscopy, imaging, and intensity. Using rhodamine B in water as a case study, we perform measurements as a function of solute concentration, temperature, wavelength, time, near-infrared laser power, visible excitation wavelength, and isotope effect.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
School of Physical Sciences, University of Chinese Academy of Sciences (UCAS), Beijing 100049, China.
It is well established that the long-range van der Waals or thermal Casimir interaction between two semi-infinite dielectrics separated by a distance H is screened by an intervening electrolyte. Here we show how this interaction is modified when an electric field of strength E is applied parallel to the dielectric boundaries, leading to a nonequilibrium steady state with a current. The presence of the field induces a long-range thermal repulsive interaction, scaling just like the thermal Casimir interaction between dielectrics without the intervening electrolyte, i.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
Alignment effects caused by a heat flow in the cholesteric liquid crystal phase of three coarse grained molecular model systems based on the Gay-Berne potential have been studied by molecular dynamics simulation. In order to keep the systems homogeneous, the Evans heat flow algorithm, where a fictitious mechanical heat field rather than a temperature gradient drives the heat flow, was used. It was found that the cholesteric axis orients in such a way that the heat flow and thereby the irreversible energy dissipation rate are minimized.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Center for Quantum Information and Quantum Control and Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Designing a model of retinal isomerization in rhodopsin, the first step in vision, that accounts for both experimental transient and stationary state observables is challenging. Here, multiobjective Bayesian optimization is employed to refine the parameters of a minimal two-state-two-mode () model describing the photoisomerization of retinal in rhodopsin. The optimized retinal model predicts excitation wavelength-dependent fluorescence spectra that closely align with experimentally observed non-Kasha behavior in the nonequilibrium steady state.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Department of Physics, IQIM, California Institute of Technology, Pasadena, California 91125, USA.
External coherent fields can drive quantum materials into nonequilibrium states, revealing exotic properties that are unattainable under equilibrium conditions-an approach known as "Floquet engineering." While optical lasers have commonly been used as the driving fields, recent advancements have introduced nontraditional sources, such as coherent phonon drives. Building on this progress, we demonstrate that driving a metallic quantum nanowire with a coherent wave of terahertz phonons can induce an electronic steady state characterized by a persistent quantized current along the wire.
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