评估Thomas-Fermi-von Weizsäcker密度函数中的错误来源
Bishal Thapa1,2, Xin Jing3,4, John E Pask5
1Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, USA.
The Journal of chemical physics
|June 1, 2023
概括
托马斯 - 费米 - - 韦兹塞克 (TFW) 近似得出与科恩 - 沙姆DFT相比不准确的能量,尽管电子密度相似. 这个错误源于TFW对电子动能线性响应的表现不佳.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 量子化学是一种量子化学.
- 材料科学是一种材料科学.
背景情况:
- 托马斯 - 费米 - - 韦兹萨克 (TFW) 模型是一个无轨道密度的函数式近似.
- 科恩-沙姆密度函数理论 (DFT) 是电子结构计算的广泛使用的准确方法.
研究的目的:
- 与Kohn-Sham DFT相比,在TFW近似中确定能源错误的来源.
- 调查TFW模型在应变和原子位移下对各种材料性能的准确性.
主要方法:
- 对各种材料和晶体结构的数值研究.
- 分析基本状态电子密度和能量.
- TFW和Kohn-Sham DFT计算之间的比较.
- 在TFW近似中对线性响应属性的评估.
主要成果:
- TFW地面状态电子密度与Kohn-Sham DFT密度非常接近.
- 与Kohn-Sham DFT价值相比,TFW能量的显著偏差被观察到.
- TFW近似表现得很差,代表了电子运动能量的线性反应.
- 使用TFW密度的非自相一致的Kohn-Sham计算与自相一致的结果很好地一致.
结论:
- TFW能量错误的主要来源在于它对电子动能线性响应的不充分处理.
- TFW无轨道的DFT可以提供精确的电子密度,但不能提供精确的能量.
- 非自相一致的Kohn-Sham计算提供了一个计算效率高的替代方案,对能量具有很高的准确性.
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