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arXiv 1901.08138physics.chem-phcond-mat.soft
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连续溶剂化中的溶剂感知界面

Solvent-aware Interfaces in Continuum Solvation

Oliviero Andreussi, Nicolas Georg Hörmann, Francesco Nattino, Giuseppe Fisicaro, Stefan Goedecker, Nicola Marzari

摘要:

以有效方式处理溶剂和电解质效应的连续介质模型在量子化学模拟中具有悠久的传统,现在也被引入到计算凝聚态和材料模拟中。连续介质模型的一个关键因素是溶质腔的选择,即定义量子力学(QM)系统和连续介质嵌入环境所占据的空间区域之间的尖锐或光滑边界。虽然大多数溶质为基础的方法开发的模型具有可比性和高精度时,适用于小的有机分子,他们可以引入显着的文物时,考虑复杂系统。作为一个例子,凝聚态模拟经常处理支持,目前开放的结构。类似地,连续溶剂的非物理口袋可能出现在具有多个分子组分的系统中。在这里,我们引入了一种溶剂感知方法来消除非物理效应,其中小于单个溶剂分子大小的空间区域仍然可以填充连续环境。我们这样做,通过定义一个平滑变化的溶质腔,克服了几个简单的溶质为基础的定义的局限性。这种新的方法适用于任何光滑的连续界面的局部定义,是它的基础上的电子密度或原子的位置的QM系统。它产生相对于QM自由度连续可微的边界,从而产生精确的力和/或Kohn-Sham势。在半导体衬底和显式水衬底上的基准确认了该方法的灵活性和准确性,并提供了一套通用的参数,用于具有开放结构和/或显式液体成分的凝聚态系统。

英文摘要:

Continuum models to handle solvent and electrolyte effects in an effective way have a long tradition in quantum-chemistry simulations and are nowadays also being introduced in computational condensed-matter and materials simulations. A key ingredient of continuum models is the choice of the solute cavity, i.e. the definition of the sharp or smooth boundary between the regions of space occupied by the quantum-mechanical (QM) system and the continuum embedding environment. Although most of the solute-based approaches developed lead to models with comparable and high accuracy when applied to small organic molecules, they can introduce significant artifacts when complex systems are considered. As an example, condensed-matter simulations often deal with supports that present open structures. Similarly, unphysical pockets of continuum solvent may appear in systems featuring multiple molecular components. Here, we introduce a solvent-aware approach to eliminate the unphysical effects where regions of space smaller than the size of a single solvent molecule could still be filled with a continuum environment. We do this by defining a smoothly varying solute cavity that overcomes several of the limitations of straightforward solute-based definitions. This new approach applies to any smooth local definition of the continuum interface, being it based on the electronic density or the atomic positions of the QM system. It produces boundaries that are continuously differentiable with respect to the QM degrees of freedom, leading to accurate forces and/or Kohn-Sham potentials. Benchmarks on semiconductor substrates and on explicit water substrates confirm the flexibility and the accuracy of the approach and provide a general set of parameters for condensed-matter systems featuring open structures and/or explicit liquid components.

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