Expeditious Stochastic Calculation of Random-Phase Approximation Energies for Thousands of Electrons in Three Dimensions.
Expeditious Stochastic Calculation of Random-Phase Approximation Energies for Thousands of Electrons in Three Dimensions.
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三维数千个电子的随机相位近似能量的快速随机计算。
DOI：
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发表时间：
2012
影响因子：
5.7
通讯作者：
R. Baer
中科院分区：
文献类型：
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作者：
D. Neuhauser;E. Rabani;R. Baer
提出了密度泛函理论中随机相位近似相关能的快速计算方法。相关能量由投影RPA响应矩阵上的轨迹给出，该轨迹由随机摄动向量的随机方法获得。对于每个电子总能量的固定统计误差，该方法最多与系统大小成二次标度；然而，在实际应用中，由于自平均，随着系统的增长，它需要的统计采样更少，性能接近线性缩放。我们通过计算超过1500个电子的硒化镉和硅纳米晶体的RPA相关能来证明该方法。我们发现每个电子的RPA相关能在很大程度上与纳米晶体的尺寸无关。此外，我们还展示了一种相关采样技术，可以计算出两种稍微扭曲的构型之间的能量差，并且具有缩放和类似于每个电子总能量的统计误差。
A fast method is developed for calculating the random phase approximation (RPA) correlation energy for density functional theory. The correlation energy is given by a trace over a projected RPA response matrix, and the trace is taken by a stochastic approach using random perturbation vectors. For a fixed statistical error in the total energy per electron, the method scales, at most, quadratically with the system size; however, in practice, due to self-averaging, it requires less statistical sampling as the system grows, and the performance is close to linear scaling. We demonstrate the method by calculating the RPA correlation energy for cadmium selenide and silicon nanocrystals with over 1500 electrons. We find that the RPA correlation energies per electron are largely independent of the nanocrystal size. In addition, we show that a correlated sampling technique enables calculation of the energy difference between two slightly distorted configurations with scaling and a statistical error similar to that of the total energy per electron.