Energy conservation in adaptive hybrid atomistic/coarse-grain molecular dynamics
Energy conservation in adaptive hybrid atomistic/coarse-grain molecular dynamics
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DOI：
10.1021/ct600323n
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发表时间：
2007-05-01
影响因子：
5.5
通讯作者：
Parrinello, Michele
中科院分区：
文献类型：
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作者：
Ensing, Bernd;Nielsen, Steven O.;Parrinello, Michele
多尺度计算机模拟算法需要描述复杂的分子系统的事件发生在一个范围内的时间和长度尺度。真正的多尺度模拟必须解决界面或握手问题，即在系统的不同空间区域将不同级别的描述耦合在一起。如果不同分辨率的空间区域随时间移动，或者如果允许材料流过区域间边界，则必须在多尺度算法中引入一种机制，以允许材料动态地改变其表示。虽然这种机制在许多情况下是非常可取的，但它充满了技术困难。在这里，我们提出了一个分子动力学模拟算法，这是多尺度的时间和空间。我们用辅助项补充势能和动能表达式，以便将总能量恢复为守恒量，即使在模拟过程中自由度总数发生变化。这对于适当评估自适应混合算法的质量至关重要，特别是，它允许我们调整CRAMA级别的层次结构以优化集成方案。
Multiscale computer simulation algorithms are required to describe complex molecular systems with events occurring over a range of time and length scales. True multiscale simulations must solve the interface, or hand-shaking, problem of coupling together different levels of description in different spatial regions of the system. If the spatial regions of different resolution move over time, or if material is allowed to flow over the inter-region boundaries, a mechanism must be introduced into the multiscale algorithm to allow material to dynamically change its representation. While such a mechanism is highly desirable in many instances, it is fraught with technical difficulties. Here, we present a molecular dynamics simulation algorithm which is multiscale in both time and space. We supplement the potential and kinetic energy expressions with auxiliary terms in order to recover the total energy as a conserved quantity, even when the total number of degrees of freedom changes during the simulation. This is crucial for a proper assessment of the quality of adaptive hybrid algorithms, and in particular, it allows us to tune the hierarchy of RESPA levels to optimize the integration scheme.