论文标题
通过与运动方程耦合群集理论的连接来改善RPA激发能的途径
A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory
论文作者
论文摘要
我们重新审查了动作方程耦合群集（EOM-CC）与伯克尔巴赫最近探索的随机相位近似（RPA）之间的连接[J.化学物理。 149，041103（2018）]并统一了这些对地面和激发态的各种方法的各种方法论方面。建立了基于环耦合群集双打的RPA和EOM-CC的身份，并具有数值结果，这是基于理论上的证明。然后，我们引入了EOM-CC和RPA方法家族中的新近似值，评估其数值性能，并探索一种获得这种连接的好处以改善激发能量的方法。我们的结果表明，增加扰动校正来解释双重激发和缺失的交换效应可能会导致估计值显着改善。
We revisit the connection between equation-of-motion coupled cluster (EOM-CC) and random phase approximation (RPA) explored recently by Berkelbach [J. Chem. Phys. 149, 041103 (2018)] and unify various methodological aspects of these diverse treatment of ground and excited states. The identity of RPA and EOM-CC based on the ring coupled cluster doubles is established with numerical results which was proved previously on theoretical grounds. We then introduce new approximations in EOM-CC and RPA family of methods, assess their numerical performance and explore a way to reap the benefits of such a connection to improve on excitation energies. Our results suggest that addition of perturbative corrections to account for double excitations and missing exchange effects could result in significantly improved estimates.
