Communication: Can excitation energies be obtained from orbital energies in a correlated orbital theory?
Communication: Can excitation energies be obtained from orbital energies in a correlated orbital theory?
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DOI：
10.1063/1.5052442
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发表时间：
2018-10-07
影响因子：
4.4
通讯作者：
Bartlett, Rodney J.
中科院分区：
文献类型：
--
作者：
Andrade Haiduke, Roberto Luiz;Bartlett, Rodney J.
这项工作表明，垂直激发能（表征为单电子过程）可以用由相关算符建立的自洽场问题的单粒子解来表示。对于系统(M)中的i -> a跃迁，有两种可选的方法来实施这一建议：(1)仅使用从i （M+）轨道移除电子后达到的阳离子种的特征值，或(2)将这些量与中性M系统中与i轨道相关的特征值结合起来。我们证明，从运动方程形式中得到的特征值，包括电离势和电子亲和的单次和双次替换，在通过任何途径再现这些电子跃迁能方面都表现出色，平均绝对偏差（MADs）在0.02至0.06 eV之间。此外，量子理论计划（QTP）家族的Kohn-Sham密度泛函理论（KS-DFT）方法在第二种方法方面提供了很好的结果（MADs从0.21到0.47 eV）。然而，只要只考虑M+的特征值，尽管QTP泛函各自的激发能仍然合理（MADs在0.55和0.74 eV之间），DFT就不会那么成功。最终，这些关系可以作为一个新的一致性条件来发展相关轨道理论的KS-DFT近似。AIP出版社出版。
This work shows that vertical excitation energies (characterized as single-electron processes) can be expressed in terms of one-particle solutions from a self-consistent field problem built by means of correlated operators. There are two alternative ways of enforcing this proposal for i -> a transitions in a system (M): (1) by using only eigenvalues obtained for the cationic species reached after the removal of an electron from orbital i (M+) or (2) by combining these quantities with the eigenvalue associated with orbital i from the neutral M system. We demonstrate that those eigenvalues derived from the equation-of-motion formalism in terms of the coupled cluster approach including single and double substitutions for ionization potentials and electron affinities show excellent performance in reproducing these electronic transition energies by either path, with mean absolute deviations (MADs) between 0.02 and 0.06 eV. Moreover, the Kohn-Sham Density Functional Theory (KS-DFT) methods from the Quantum Theory Project (QTP) family provide nice results in terms of the second approach (MADs from 0.21 to 0.47 eV). However, DFT is not as successful as long as one takes into account only the eigenvalues of M+, although the respective excitation energies from QTP functionals are still reasonable (MADs between 0.55 and 0.74 eV). Ultimately, these relations can be used as a new consistency condition to develop KS-DFT approximations to the correlated orbital theory. Published by AIP Publishing.