A route to improving RPA excitation energies through its connection to equation-of-motion coupled cluster theory
Abstract
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 15, 2020
- Source ID
- 10.1063/5.0023862
Entities
People
- Ajith Perera
- Rodney J. Bartlett
- Varun Rishi
Organizations
- Army Research Office
- California Institute of Technology
- National Science Foundation
- University of Florida