论文标题
评估二阶静态筛选的交换校正对相关能量的随机相位近似
Assessment of the second-order statically screened exchange correction to the random phase approximation for correlation energies
论文作者
论文摘要
随着电子间距离的增加，通过其他电子的存在筛选电子电子相互作用成为电子相关的主要来源。这种效果由随机相近似（RPA）描述，因此，这是计算弱相互作用的一种有前途的方法。 RPA的成功取决于取消错误，这可以追溯到违反4点顶点的交叉对称性，从而导致大量高估的总相关能。通过将二阶屏蔽交换（SOSEX）添加到相关能量中，该问题大大减少了。在绝热连接（AC）Sosex形式主义中，二阶交换项中的两个电子电子交互线之一是动态筛选的（Sosex（$ W $，$ v_c $））。相关的SOSEX表达式，其中两个电子 - 电子交互线均已静态筛选（Sosex（$ W（0）$，$ W（0）$）），从$ g3w2 $贡献电子自能量的贡献。与Sosex（$ W $，$ V_C $）相反，对此相关能量表达式的评估不需要昂贵的数值集成，因此从计算角度来看是有利的。我们将静态筛选变体的准确性与RPA和RPA+Sosex（$ W $，$ v_c $）的精度进行了比较。尽管这两种方法都因屏障高度而失败，但Sosex（$ W（0）$，$ W（0）$）与Sosex（$ W $，$ v_c $）非常吻合，用于充电激发和非共价交互作用，在这些互动中，它们会导致对RPA的重大改进。
With increasing inter-electronic distance, the screening of the electron-electron interaction by the presence of other electrons becomes the dominant source of electron correlation. This effect is described by the random phase approximation (RPA) which is therefore a promising method for the calculation of weak interactions. The success of the RPA relies on the cancellation of errors, which can be traced back to the violation of the crossing symmetry of the 4-point vertex, leading to strongly overestimated total correlation energies. By addition of second-order screened exchange (SOSEX) to the correlation energy, this issue is substantially reduced. In the adiabatic connection (AC) SOSEX formalism, one of the two electron-electron interaction lines in the second-order exchange term is dynamically screened (SOSEX($W$,$v_c$)). A related SOSEX expression in which both electron-electron interaction lines are statically screened (SOSEX($W(0)$,$W(0)$)) is obtained from the $G3W2$ contribution to the electronic self-energy. In contrast to SOSEX($W$,$v_c$), the evaluation of this correlation energy expression does not require an expensive numerical frequency integration and is therefore advantageous from a computational perspective. We compare the accuracy of the statically screened variant to RPA and RPA+SOSEX($W$,$v_c$) for a wide range of chemical reactions. While both methods fail for barrier heights, SOSEX($W(0)$,$W(0)$) agrees very well with SOSEX($W$,$v_c$) for charged excitations and non-covalent interactions where they lead to major improvements over RPA.
