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

Rishi, Varun and Perera, Ajith and Bartlett, Rodney J. (2020) A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory. Journal of Chemical Physics, 153 (23). Art. No. 234101. ISSN 0021-9606.

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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 treatments 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.

Item Type:Article
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URLURL TypeDescription Paper
Rishi, Varun0000-0003-0317-3815
Perera, Ajith0000-0002-9520-9514
Bartlett, Rodney J.0000-0003-3865-9639
Additional Information:© 2020 Published under license by AIP Publishing. Submitted: 3 August 2020; Accepted: 27 November 2020; Published Online: 15 December 2020. V.R. thanks Professor Ed Valeev, postdoctoral advisor at Virginia Tech, for the encouragement to pursue the project and support from U.S. National Science Foundation grants (Award Nos. 1550456 and 1800348). This work was supported by the United States Army Research Office (ARO Grant No. W911NF-16-1-0260). Data Availability: The data that support the findings of this study are available within the article.
Funding AgencyGrant Number
Army Research Office (ARO)W911NF-16-1-0260
Issue or Number:23
Record Number:CaltechAUTHORS:20200901-122036933
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105203
Deposited By: Tony Diaz
Deposited On:08 Sep 2020 20:01
Last Modified:15 Dec 2020 21:37

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