AI 中文总结
本研究探究多种碱金属、碱土金属及氯离子的耦合动力学，发现其振动功率谱的晃动频率对同位素质量有不同敏感性，或可作为离子溶剂化及类霍夫迈斯特效应的特征。
AI 中文摘要
离子与第一水合层水分子的耦合动力学影响诸多过程，包括离子扩散、水填充纳米孔中的选择性离子输运，以及离子配对、离子吸附和金属-配体结合反应的动力学。本研究从同位素质量依赖性的视角，探究碱金属（Li、Na、K、Rb、Cs）、碱土金属（Mg、Ca、Sr、Ba）及氯离子的这类耦合动力学。结果与此前水中离子扩散系数同位素质量依赖性的测量数据，以及此前水中离子高频动力学的从头算结果相验证。研究发现，水中离子的振动功率谱始终呈现两个或三个峰，即离子在溶剂化壳层内存在多个晃动频率，这与此前针对本研究中部分物种的报道一致。这些频率对同位素质量具有不同的敏感性，可作为离子溶剂化过程的特征（如离子取向第一水合层水分子的倾向），且可能与类霍夫迈斯特效应相关，包括不同金属对核糖核酸（RNA）的相对亲和力。
英文摘要
The coupled dynamics of ions and water molecules in their first hydration shell impact a variety of processes including ion diffusion, selective ion transport in water-filled nanopores, and the kinetics of ion-pairing, ion adsorption, and metal-ligand binding reactions. In this work, we study these coupled dynamics for alkali metals (Li, Na, K, Rb, Cs), alkaline Earth metals (Mg, Ca, Sr, Ba), and chloride through the lens of their dependence on ion isotopic mass. Results are validated against previous measurements of the isotopic mass-dependence of ion diffusion coefficients in water and previous ab initio calculations of ion high-frequency dynamics in water. We find that the vibrational power spectra of ions in water consistently exhibit either two or three peaks, i.e., ions have several rattling frequencies within their solvations shells as previously reported for a subset of the species examined here. These frequencies have different sensititivies to isotopic mass that may serve as signatures of ion solvation processes (such as the tendency of ions to orient their first-shell water molecules) and that also may relate to Hofmeister-like effects including the relative affinity of different metals for ribonucleic acid (RNA).
Comments27 pages total, including 4 pages of Supplementary Information; 7 figures (6 main, 1 supplementary) and 7 tables (including 5 supplementary)
