Heindel Joseph P, Xantheas Sotiris S
Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.
Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K1-83, Richland, Washington 99352, United States.
J Chem Theory Comput. 2021 Apr 13;17(4):2200-2216. doi: 10.1021/acs.jctc.0c01309. Epub 2021 Mar 12.
We present a detailed study of the many-body expansion (MBE) for alkali metal and halide ion-water interactions and quantify the effect of these ions on the strength of the surrounding aqueous hydrogen bonding environment. Building on our previous work on neutral water clusters [J. P. Heindel and S. S. Xantheas, (11), 6843-6855 (2020)], we carry out the MBE for the alkali metal and halide ion-water clusters, Z(HO), where Z = Li, Na, K, Rb, Cs, F, Cl, Br, and I and compare them with the results for a pure water cluster with the same number of "bodies", viz., (HO). The 2-B ion-water (I-W) interaction accounts for a larger percentage of the total cluster binding energy compared to a pure water cluster of the same size, with the total 3-B term being smaller and of opposite sign (repulsive), whereas higher order terms are essentially negligible. The same oscillating behavior around zero for the MBE terms higher than the 5-B with a basis set that was reported for water clusters is also observed for the ion-water clusters considered here, with the basis set superposition error (BSSE) corrections amending this as in the water cluster case. A remarkable, linear anticorrelation between the total 2-B (I-W), the total 2-B (W-W), and also the 3-B (W-W-W) interactions is found, quantifying the effect of the different ions in disrupting and altering (weakening) the neighboring hydrogen bonded water network: stronger (I-W) interactions result in weaker (W-W) interactions. Additional linear correlations across the two series of alkali metals and halide ions were found between the 3-B (I-W-W) and the 2-B (I-W) as well as between the 3-B (I-W-W) and the 3-B (W-W-W) interactions, suggesting the existence of previously unrealized underlying physics governing these 2-B intermolecular and 3-B collective interactions. Our results further suggest a universal behavior of the two different families of ions (alkali metals and halides) for both the correlations of the various components of the total binding energies and the estimate of the 2-B BSSE correction, which is reported to follow a common profile for ion-water and water-water interactions when cast in terms of reduced distances and energies of the respective dimers. We expect the current results that quantify the interplay between ion-water and water-water interactions in aqueous clusters to impact the development of classical, -based force fields for monatomic ion solvation, whereas the insights into the nature of the BSSE to be critical in future -based, many-body molecular dynamics studies.
我们对碱金属和卤离子与水的相互作用进行了多体展开（MBE）的详细研究，并量化了这些离子对周围水氢键环境强度的影响。基于我们之前关于中性水团簇的工作[J. P. 海因德尔和S. S. 赞泰亚斯，(11)，6843 - 6855(2020)]，我们对碱金属和卤离子水团簇Z(HO)进行了MBE，其中Z = Li、Na、K、Rb、Cs、F、Cl、Br和I，并将它们与具有相同“体”数的纯水团簇(HO)的结果进行比较。与相同大小的纯水团簇相比，二体离子 - 水（I - W）相互作用在总团簇结合能中占更大比例，而三体项总和更小且符号相反（排斥），而高阶项基本可忽略不计。对于此处考虑的离子 - 水团簇，也观察到了高于五体的MBE项围绕零的相同振荡行为，这与水团簇报道的情况相同，基组叠加误差（BSSE）校正也如在水团簇情况中那样修正了此行为。发现总二体（I - W）、总二体（W - W）以及三体（W - W - W）相互作用之间存在显著的线性反相关，量化了不同离子对破坏和改变（削弱）相邻氢键水网络的影响：更强的（I - W）相互作用导致更弱的（W - W）相互作用。在碱金属和卤离子的两个系列之间还发现了三体（I - W - W）与二体（I - W）以及三体（I - W - W）与三体（W - W - W）相互作用之间的额外线性相关性，这表明存在尚未被认识到的潜在物理规律来支配这些二体分子间和三体集体相互作用。我们的结果进一步表明，对于总结合能各组分的相关性以及二体BSSE校正的估计，这两类不同离子（碱金属和卤化物）具有普遍行为，当根据各自二聚体的约化距离和能量来表示时，据报道离子 - 水和水 - 水相互作用遵循共同的规律。我们期望当前量化水团簇中离子 - 水和水 - 水相互作用之间相互作用的结果会影响基于经典的单原子离子溶剂化力场发展，而对BSSE性质的深入理解在未来基于多体的分子动力学研究中将至关重要。
