Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202-9024, USA.
J Chem Phys. 2010 Jul 28;133(4):044107. doi: 10.1063/1.3460594.
Using the technique of Perdew and Levy [Phys. Rev. B 31, 6264 (1985)], it is shown that both the density function theory (DFT)-in-DFT and wave function theory (WFT)-in-DFT embedding approaches are formally correct in studying not only the ground state but also a subset of the excited states of the total system. Without further approximations, the DFT-in-DFT embedding approach results in a pair of coupled Euler-Lagrange equations. In contrast to DFT-in-DFT, the WFT-in-DFT approach is shown to ensure a systematic description of excited states if such states are mainly related to excitations within the embedded subsystem. Possible ways for the practical realization of the WFT-in-DFT approach for studying excited states are briefly discussed.
利用 Perdew 和 Levy 的技术[Phys. Rev. B 31, 6264 (1985)]，表明密度泛函理论（DFT）-在-DFT 和波函数理论（WFT）-在-DFT 嵌入方法在研究整个系统的基态和部分激发态时都是形式上正确的。在没有进一步近似的情况下，DFT-in-DFT 嵌入方法导致了一对耦合的欧拉-拉格朗日方程。与 DFT-in-DFT 不同，WFT-in-DFT 方法如果这些状态主要与嵌入子系统内的激发相关，则被证明可以系统地描述激发态。简要讨论了用于研究激发态的 WFT-in-DFT 方法的实际实现的可能途径。
