在多体扩展中对高阶术语进行可扩展的通用选:算法,开源实现和演示.
Dustin R Broderick1, John M Herbert1
1Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
The Journal of chemical physics
|November 3, 2023
概括
本研究引入了一种新的算法和开源软件,以克服大型量子化学系统的多体膨胀计算中的组合挑战. 该方法可以在显著降低计算成本的情况下进行准确的大规模电子结构计算.
科学领域:
- 计算化学的计算化学
- 量子化学 是一个量子化学.
- 材料科学 材料科学 材料科学
背景情况:
- 多体扩展 (MBE) 对基于碎片的方法至关重要,以减少初始量子化学的计算成本.
- 在MBE中,更高阶项的组合复杂性 (n ≥ 4) 限制了其实际应用.
- 对于大型系统来说,准确的电子结构计算仍然是一个巨大的挑战,因为需要计算扩展.
研究的目的:
- 开发一种高效的算法和软件,以克服多体膨胀计算中的组合瓶.
- 为了使比以前可行的大得多的系统能够进行准确的初始电子结构计算.
- 调查MBE中高阶术语的行为和必要性.
主要方法:
- 开发了一个自下而上的基于能源的选算法来管理组合增长.
- 在一个开源软件包"Fragmet"中实现了算法.
- 集成了一种轻量级的半实证方法用于子系统除,并使用基于图表的计算管理.
主要成果:
- 在 (H2O) 64个集群上成功执行了四体计算,使用<10%的子系统,准确度高 (超级系统的0.1kcal/mol/monomer范围内).
- 对 (H2O) 20 个集群进行了高达 n=8 的 n-body 计算,通过选证明了终结.
- 实现了迄今为止使用ab initio电子结构理论进行的最大的n体计算.
结论:
- 开发的算法和软件有效地减轻了MBE中的组合问题.
- 在MBE计算中的高阶n体项在很大程度上是基础集叠加错误的产物.
- 这项工作显著提高了将基于碎片的方法应用于非常大的分子系统的可行性.
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