Faculty of Physics and Center for Computational Materials Sciences, University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria.
Institute for Theoretical Physics, Technical University of Vienna, Wiedner Hauptstraße 8-10/136, 1040 Vienna, Austria.
J Chem Phys. 2019 Dec 7;151(21):214106. doi: 10.1063/1.5128415.
We present a method to approximate post-Hartree-Fock correlation energies by using approximate natural orbitals obtained by the random phase approximation (RPA). We demonstrate the method by applying it to the helium atom, the hydrogen and fluorine molecule, and to diamond as an example of a periodic system. For these benchmark systems, we show that RPA natural orbitals converge the MP2 correlation energy rapidly. Additionally, we calculated full configuration interaction energies for He and H, which are in excellent agreement with the literature and experimental values. We conclude that the proposed method may serve as a compromise to reach good approximations to correlation energies at moderate computational cost, and we expect the method to be especially useful for theoretical studies on surface chemistry by providing an efficient basis to correlated wave function based methods.
我们提出了一种通过使用随机相位近似（RPA）得到的近似自然轨道来逼近后哈特ree-fock 相关能的方法。我们通过将其应用于氦原子、氢分子和氟分子以及金刚石（作为周期性系统的一个例子）来演示该方法。对于这些基准系统，我们表明 RPA 自然轨道迅速收敛 MP2 相关能。此外，我们还计算了 He 和 H 的完全组态相互作用能，与文献和实验值吻合得非常好。我们得出结论，该方法可以作为一种折衷方案，以在中等计算成本下达到对相关能的良好逼近，我们预计该方法通过为相关波函数方法提供有效的基础，对表面化学的理论研究特别有用。
