Multiscale Modeling of Chemistry in Water: Are We There Yet?
Multiscale Modeling of Chemistry in Water: Are We There Yet?
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DOI：
10.1021/ct4005596
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发表时间：
2013-12-01
影响因子：
5.5
通讯作者：
Sautet, Philippe
中科院分区：
文献类型：
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作者：
Bulo, Rosa E.;Michel, Carine;Sautet, Philippe
本文批判性地评估了结合量子力学/分子力学（QM/MM）方法在水中化学计算描述方面的最新进展，并为建立定制的水过程多尺度模拟提供了指导方针。我们区分了结构性能和动态性能，因为一些任务，例如NMR或UV-vis光谱的再现，只需要结构精度，而其他任务，即反应机理，也需要准确的动态数据。作为一般水溶液的模型系统，这些方法在MM水分子环境中的QM水簇上进行了测试。关键的困难是描述QM分子可能扩散到MM区域，反之亦然。柔性内区系综分离器（FIRES）方法将QM溶剂分子限制在活性区域内。排序自适应分区（SAP）、基于差异的自适应溶剂化（DAS）和缓冲力（BF）都是使用缓冲带的自适应方法，在缓冲带中溶剂分子逐渐从QM适应到MM（反之亦然）。SAP和DAS的成本相对较高，而BF速度快，但牺牲了能量和动量的守恒。在一个无限小的缓冲区的极限下，DAS和SAP变得等效，也被讨论并称为突变。DAS、BF和唐突三种结构精度相近，结构精度最高。FIRES对于深度定位于QM区域的动态特性表现得非常好。通过消除，DAS成为结构性能和动态性能之间的最佳整体折衷。消除缓冲区（唐突）提高了效率，仍然会带来令人惊讶的好结果。虽然许多新口味都不是完美的，但所有这些新领域已经允许对水溶液的结构和动态特性进行广泛的精确描述。
This paper critically evaluates the state of the art in combined quantum mechanical/molecular mechanical (QM/MM) approaches to the computational description of chemistry in water and supplies guidelines for the setup of customized multiscale simulations of aqueous processes. We differentiate between structural and dynamic performance, since some tasks, e.g., the reproduction of NMR or UV-vis spectra, require only structural accuracy, while others, i.e., reaction mechanisms, require accurate dynamic data as well. As a model system for aqueous solutions in general, the approaches were tested on a QM water cluster in an environment of MM water molecules. The key difficulty is the description of the possible diffusion of QM molecules into the MM region and vice versa. The flexible inner region ensemble separator (FIRES) approach constrains QM solvent molecules within an active (QM) region. Sorted adaptive partitioning (SAP), difference-based adaptive solvation (DAS), and buffered-force (BF) are all adaptive approaches that use a buffer zone in which solvent molecules gradually adapt from QM to MM (or vice versa). The costs of SAP and DAS are relatively high, while BF is fast but sacrifices conservation of both energy and momentum. Simulations in the limit of an infinitely small buffer zone, where DAS and SAP become equivalent, are discussed as well and referred to as ABRUPT. The best structural accuracy is obtained with DAS, BF, and ABRUPT, all three of similar quality. FIRES performs very well for dynamic properties localized deep within the QM region. By means of elimination DAS emerges as the best overall compromise between structural and dynamic performance. Eliminating the buffer zone (ABRUPT) improves efficiency and still leads to surprisingly good results. While none of the many new flavors are perfect, all together this new field already allows accurate description of a wide range of structural and dynamic properties of aqueous solutions.