Quantum-Classical Adaptive Resolution Simulations of Aqueous Solvation: Effects of Hydrogen Spatial Delocalization

在我们以前的工作中，富勒烯第一溶剂化壳层中水的相关性质已经被认为是局域性的。然而，与基于空间原子空间离域的量子模型相比，经典的水模型往往提供了过于严格的溶剂化结构。因此，尽管可以得出结论，富勒烯分子在水中聚集的一般机制是一个水中介的过程，需要分子在感受到互易存在之前非常接近，形成包括两个富勒烯分子的唯一溶剂壳的障碍在使用量子模型还是经典模型时有很大的不同。通过大幅度去除氢键自由度的自适应分辨模拟技术(ADRESS)被证明是得出这一结论的一种有效方法。下一步，利用同样的技术，人们可以将研究扩展到非平衡情况，在这种情况下，外部电场可以破坏或进一步加强水的局域性，从而操纵氢键网络的行为。这进而意味着要找到聚合过程的最佳外部(物理)操作，以获得特定的期望结果(聚合/非聚合)。

Relevant properties of water in the first solvation shell of thefullerene have been shown in our previous work to be deemed local.However, classical models of water tend to provide a solvation structurefar too rigid compared to quantum model based on the spatialdelocalization of atoms in space.As a consequence, while it can be concluded that the general mechanismof aggregation of fullerene molecules in water, being a water-mediatedprocess, requires that the molecules come very close before they feelthe reciprocal presence, the barrier for the formation of a uniquesolvation shell that includes two fullerene molecules differsconsiderably on whether a quantum or a classical model is used. Theadaptive resolution simulation technique (AdResS) by drasticallyremoving the hydrogen bonding degrees of freedom turned out to be apowerful method for reaching such conclusions. Next, with the use of thesame technique, one may extend the study to a non-equilibrium situationwhere an external electric field may either break or strengthen furtherthe properties of locality of water and thus manipulate the behaviour ofthe hydrogen bonding network. This in turn implies to found an optimalexternal (physical) manipulation of the aggregation process in order toobtain a particular wished result (aggregation/non-aggregation).