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Quantum Simulation of Polarized Light-Induced Electron Transfer with a Trapped-Ion Qutrit System
Electron transfer within and between molecules is crucial in chemistry, biochemistry, and energy science. Here this study describes a quantum simulation method that explores the influence of light polarization on electron transfer between two molecules. By implementing precise and coherent control among the quantum states of trapped atomic ions, we can induce quantum dynamics that mimic the electron-transfer dynamics in molecules. We use three-level systems (qutrits), rather than traditional two-level systems (qubits), to enhance the simulation efficiency and realize high-fidelity simulations of electron-transfer dynamics. We treat the quantum interference between the electron coupling pathways from a donor with two degenerate excited states to an acceptor and analyze the transfer efficiency. We also examine the potential error sources that enter the quantum simulations. The trapped-ion systems have favorable scalings with system size compared to those of classical computers, promising access to richer electron-transfer simulations.
Molecular Dynamics Simulations of Ion-Containing Polymers Using Generic Coarse-Grained Models
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Correlations between Molecular Structure, Solvation Topology, and Transport Properties of Aqueous Organic Flow Battery Electrolyte Solutions
Aqueous organic redox flow batteries (AORFBs) are considered promising technologies for storing energy generated from renewable resources. However, designing organic electrolyte molecules is limited by gaps between fundamental understanding of coupling between solvation structure and dynamics, and macroscopic transport properties like viscosity. Herein, we used molecular dynamics simulations to understand correlations between ionic molecular structures, ion clustering, and transport properties in 2,3-dihydrophenazine (2,3-DHP), a promising AORFB anolyte. We show that experimentally measured viscosity can be reproduced from simulations at relevant concentrations and that the asymmetric structure of 2,3-DHP leads to unique inhomogeneity in the solvation topology. However, order parameters and metrics need to be developed for better correlations over spatiotemporal scales, with careful consideration of the inhomogeneity of organic anolyte molecules. In conclusion, we show that the increased size and asymmetry of the anolyte leads to breakdown of assumptions within methods for determining ion transport mechanisms previously developed for Li-ion batteries.
Ultrafast Photofragmentation of Ln(hfac)3 with a Proposed Mechanism for forming High Mass Fluorinated Products
Abstract The photo-induced dissociative-ionization of lanthanide complexes Ln(hfac) 3 (Ln = Pr, Er, Yb) is studied using intense ultrafast transform limited (TL) and linearly chirped laser pulses in a time-of-flight (TOF) mass spectrometry setup. Various fluorine and Ln-containing high-mass fragments were observed in this experiment, including the molecular parent ion, which have not been seen with previous studies relying on relatively long-duration laser pulses (i.e., ns or longer). These new high-mass observations provide important formerly missing information for deducing a set of photo-fragmentation mechanistic pathways for Ln(hfac) 3 . An overall ultrafast control mechanism is proposed by combining insights from earlier studies and the fragments observed in this research to result in three main distinct photo-fragmentation processes: (a) ligand-metal charge transfer, (b) CF 3 elimination, and (c) C-C bond rotation processes. We conclude that ultrafast dissociative-ionization could be a promising technique for generating high-mass fragments for potential use in material science applications.
A transient site balance model for atomic layer etching
We present a transient site balance model of plasma-assisted atomic layer etching of silicon (Si) with alternating exposure to chlorine gas (Cl 2 ) and argon ions (Ar + ). Molecular dynamics (MD) simulation results are used to provide parameters for the model. The model couples the dynamics of a top monolayer surface region ('top layer') and a perfectly mixed subsurface region ('mixed layer'). The differential equations describing the rates of change of the Cl coverage in the two layers are transient mass balances. Model predictions include Cl coverages and rates of etching of various species from the surface as a function of Cl 2 or Ar + fluence. The simplified phenomenological model reproduces the MD simulation results well over a range of conditions. Comparing model predictions directly to experimental optical emission spectroscopy data, as reported in a previous paper, provides further evidence of the accuracy of the model.
High-voltage water-scarce hydrogel electrolytes enable mechanically safe stretchable Li-ion batteries
Soft Li-ion batteries, based on conventional organic electrolytes, face performance degradation challenges due to moisture penetration and safety concerns due to possible leakage of toxic fluorine compounds and flammable solvents under mechanical damage. We design a water-scarce hydrogel electrolyte with fluorine-free lithium salt to achieve wide electrochemical stability window (up to 3.11 volts) in ambient air without hermetic packaging while balancing high stretchability (1348%), ion conductivity (41 millisiemens per centimeter), and self-healing capabilities for mechanically and chemically safe stretchable Li-ion batteries. Molecular synergy between hydrophilicity and lithiophilicity of zwitterionic polymer backbone is revealed by molecular dynamics simulations. The battery exhibits capacity retention under harsh mechanical stresses—enduring stretching, twisting, folding, and multiple through-punctures by a needle—while self-healing from repeated through cuts by a razor blade. Stable ambient operation for 1 month over 500 charge-discharge cycles (average coulomb efficiency, 95%) is achieved. A prototype self-healing electronic system with embedded soft batteries demonstrates practical application as a durable embodied energy source.
Molecular Modeling of Gas and Ion Transport in Alkaline Battery Electrolytes
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Comments on collisional-radiative recombination of He sub 2 super plus into dissociative states.
Comments on radiative recombination of molecular helium ions into dissociative state
Some potential-energy surfaces on H sub 3 super plus computed with generalized Gaussian orbitals.
Potential energy surfaces on triatomic hydrogen molecule ion computed with generalized Gaussian orbitals
Inversion of low-energy experimental He- He super plus elastic differential scattering sections to the super 2 sigma sub g super plus and super 2 sigma sub u super plus potentials.
He-He ground state and first excited state potentials obtained from differential scattering cross sections
Intermediate-range intermolecular forces in H sub 2 super plus.
Intermediate range intermolecular forces with overlapping wave functions and exchange effects calculated for ionized H molecule using perturbation theory
Energy required for proton production by electron impact in mixtures of atomic and molecular hydrogen.
Energy required for proton and molecular hydrogen ion production by electron impact in tenuous hydrogen plasma using Maxwellian electron gas model
The spatial extent of aurorae in o/5577/ and N2/plus/ /4278/ emissions
Spatial distribution of aurorae in O and molecular nitrogen ion emissions
N2/plus/ potential-energy curves
Molecular nitrogen ion potential energy curves based on valence bond method, calculating sextet and quartet states at intermediate internuclear separation distances
Observations on pulsating auroras
Infrasonic pulsations of optical auroral luminosity in 3914 A positive molecular nitrogen ion and 5577 A O I emission measurement by double photometer system
Would shower cores or relativistic monopoles produce straight lightning.
The cause of leaders occasionally leaving old stroke channels is found to be atomic and molecular negative ions inside and outside old stroke channels, respectively. From this it is shown that the ionization in shower cores and possibly that in monopole paths would be capable of carrying a lightning leader which would then be straight and result in a straight return stroke. Artificial initiation of lightning shows that even thunderclouds without spontaneous lightning maintain large potential gradients over large areas for significant periods of time. Thundercloud conditions for straight lightning may be more favorable over ocean than land areas.