In density functional-theoretic studies of photoionized water-based systems, the role of charge localization in proton-transfer dynamics is not well understood. This is due to the inherent complexity in extracting the contributions of coupled electron-nuclear non-adiabatic dynamics in the presence of exchange and correlation functional errors. In this work, we address this problem by simulating a model system of ionized linear H-bonded water clusters using real-time Time Dependent Density Functional Theory (rt-TDDFT)-based Ehrenfest dynamics. Our aim is to understand how self-interaction error in semilocal exchange and correlation functionals affects the probability of proton transfer. In particular, we show that for H-bonded (H$_2$O)$_n^+$ chains (with $n>3$), the proton-transfer probability attains a maximum, becoming comparable to that predicted by hybrid functionals. This is because the formation of hemibonded-type geometries is largely suppressed in extended H-bonded structures. We also show how the degree of localization of the initial photo-hole is connected to the probability of a proton-transfer reaction, as well as to the separation between electronic and nuclear charge. These results are compared to those obtained with adiabatic dynamics where the initial wavefunction is allowed to relax to the ground state of the ion cluster, explaining why different functionals and dynamical approaches lead to quantitatively different results.
Hydrated Excess Protons in Acetonitrile/Water Mixtures - Solvation Species and Ultrafast Proton Motions
质子在水介质中的溶剂化结构与液体和膜中的电性质和质子输运高度相关。在环境温度下,极性液体在毫微微秒到皮秒的时间尺度上显示结构波动,对质子溶剂化有直接影响。我们应用二维红外(2D-IR)光谱以下的质子动力学在乙腈/水的混合物与Zundel阳离子H $_5$ O $_2^+$制备在纯乙腈作为基准。H $_5$ O $_2^+$质子转移模式的2D-IR光谱表明,在双最小质子势中,受波动电场驱动的随机大振幅运动。在所有情况下,过量的质子嵌入水二聚体中,形成H $_5$ O $_2^+$络合物作为主要溶剂化物质。这一观察是合理的量子力学/分子力学分子动力学模拟,包括多达4个水分子嵌入乙腈。Zundel基序在H $_7$ O $_3^+$单元中与其最近的水邻居相互作用,而没有持续的质子定位。
Proton transfer and hydronium formation in ionized water
Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY(自由电子激光科学中心,德国电子同步加速器);Center for Ultrafast Imaging, Universität Hamburg(超快成像中心,汉堡大学);University of Chemistry and Technology, Prague(布拉格化工大学);IT4Innovations, VSB – Technical University of Ostrava(IT4创新,俄斯特拉发科技大学);Department of Physics, Universität Hamburg(物理系,汉堡大学)
Two-Dimensional Water in Graphene Nanocapillaries Simulated with Different Force Fields: Rhombic Versus Square Structures, Proton Ordering, and Phase Transitions
Isotopic Fingerprints of Proton-mediated Dielectric Relaxation in Solid and Liquid Water
Austrian Institute of Technology(奥地利技术研究所);Israel Institute of Technology(以色列理工学院);University of Washington(华盛顿大学);École Polytechnique Fédérale de Lausanne(洛桑联邦理工学院);Hamburg University of Technology(汉堡工业大学)
Tracking molecular hydrogen formation from ionized water in real time
Stanford PULSE Institute, SLAC National Accelerator Laboratory(斯坦福脉冲研究所,SLAC国家加速器实验室);Department of Physics, Stanford University(斯坦福大学物理系);State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University(北京大学物理学院介观物理国家重点实验室与纳米光电前沿科学中心);Department of Physics, Kennesaw State University(肯尼索州立大学物理系);Department of Applied Physics, Stanford University(斯坦福大学应用物理系);Linac Coherent Light Source, SLAC National Accelerator Laboratory(SLAC国家加速器实验室直线相干光源);Department of Physics, Augustana University(奥古斯塔纳大学物理系)
Wien effect in interfacial water dissociation through proton-permeable graphene electrodes
强电场可以加速分子解离反应。这种被称为维恩效应的现象以前是用高压电解池观察到的,电解池产生的电场约为10^7 V m-1,足以加速弱结合分子的解离(例如,有机物和弱电解质)。对于水离解的常见情况(H2O = H+ + OH-)的维恩效应的观察仍然是难以捉摸的。在这里,我们研究了质子可渗透石墨烯电极附近界面水的解离,并观察到在达到10^8 V m-1以上的电场中反应的强烈加速。石墨烯电极的使用允许测量仅由界面水的解离产生的质子电流,而驱动反应的电场通过由相同场在石墨烯中诱导的载流子密度来监测。所观察到的质子电流的指数增加与Onsager的理论定量一致。我们的研究结果还表明,石墨烯电极可以是有价值的各种界面现象,涉及质子输运的调查。
Water structure near the surface of Weyl semimetals as catalysts in photocatalytic proton reduction
Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, Paderborn University(帕德博恩大学凝聚态动力学与可持续系统设计中心理论化学教席)
K-shell Core Electron Excitations in the Electronic Stopping of Protons in Water
由于质子束在放射肿瘤学中的应用越来越广泛,对质子辐照下液态水中核心电子激发的作用有了详细的了解变得非常重要。利用基于实时含时密度泛函理论的第一性原理非平衡态模拟方法,我们确定了电子阻止本领,即从辐照离子到电子的能量转移速率随速度的变化。电子阻止本领曲线同意定量在整个速度范围内的实验数据是可用的。另外值得注意的是,我们观察到我们的第一性原理的结果和常用的微扰理论模型之间的显着差异。水分子氧核电子的激发是决定电子阻止本领曲线超过其最大值的关键因素。在8.0 a. u的高质子速度下,核心电子的贡献占阻止本领的三分之一。(1.6 MeV)。这些K-壳层芯电子激发不仅为能量传递提供了额外的通道,而且它们还显著地影响价电子激发。在激发过程中,产生的空穴仍然高度局限于照射质子路径周围几埃的范围内,而电子则被激发远离路径。尽管K壳层电子对电子阻止本领有很大贡献,但就激发密度而言,它所起的作用相当小:即使在8.0 a. u的高质子速度下,也只有1%的空穴群包含K壳层空穴。这里揭示的激发行为与X/γ射线光子辐射明显不同,X/γ射线光子辐射是放射肿瘤学中最常用的电离辐射类型。
Spectral signatures of excess-proton waiting and transfer-path dynamics in aqueous hydrochloric acid solutions
在红外差分吸收光谱中,溶剂化过量质子的特征,如水弯曲和拉伸带之间的连续带,已经在实验上知道了很长一段时间,但迄今为止,将光谱特征与微观质子转移机制联系起来的理论基础依赖于正常模式分析。我们分析了盐酸水溶液的从头算分子动力学模拟中的过剩质子动力学。在2000 - 3000厘米$^{-1 }$范围内的连续带被证明是由于正常模式振荡的临时H $_3$ O $^+$复合物。在400 cm $^{-1}$处的另一个显著峰报告了过量质子运动与两个侧翼水分子的相对振动的耦合。两个水分子之间的实际质子转移,这对于大的水分离涉及跨越势垒,因此不是正常模式,其特征在于两个特征时间尺度:第一,转移发生的等待时间在200 - 300 fs的范围内,这导致在~100 cm $^{-1}$附近的宽弱肩,与我们的实验太赫兹光谱一致。其次,平均持续时间约为14 fs的传输事件,这产生了一个相当明确的光谱贡献约1200厘米$^{-1}$和同意的位置和宽度与以前的实验中红外光谱。
Degradation of Proton Exchange Membrane Water Electrolyzers in Accelerated Stress Tests of Dynamic Load Cycling
State Key Laboratory of Engines, Tianjin University(天津大学发动机原理国家实验室);The International Joint Institute of Tianjin University, Fuzhou, Tianjin University(天津大学福州国际联合学院);National Industry-Education Platform of Energy Storage, Tianjin University(天津大学储能产教融合平台)
Decay Processes in Cationic Alkali Metals in Microsolvated Clusters: A Complex Absorbing Potential Based Equation-of-Motion Coupled Cluster Investigation
DFT Study of Nitroxide Radicals. 1. Effects of solvent on structural and electronic characteristics of 4-amino-2,2,5,5-tetramethyl-3-imidazoline-N-oxyl