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arXiv 2008.00336physics.chem-ph
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结合运动方程耦合团簇理论改进RPA激发能的途径

A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory

Varun Rishi, Ajith Perera, Rodney J. Bartlett

摘要:

我们重新审视了Berkelbach最近探索的运动方程耦合团簇(EOM-CC)和随机相位近似(RPA)之间的联系[J. Chem. Phys. 149,041103(2018)],并统一了基态和激发态的这些不同处理的各种方法学方面。利用数值结果建立了基于环耦合簇偶的RPA和EOM-CC的同一性,并在理论上得到了证明。然后,我们介绍了新的近似EOM-CC和RPA家庭的方法,评估其数值性能,并探索一种方法来获得这样的连接的好处,以提高激发能。我们的研究结果表明,增加微扰校正,以占双激发和缺失的交换效应可能会导致显着改善的估计。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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