The intermediate state approach for doubly excited dark states in EOM-coupled-cluster theory
Abstract
Solution of dark, doubly excited states using equation-of-motion coupled-cluster (EOM-CC) usually equires at least triple excitations or even quadruples beyond the standard singles and doubles (EOM-CCSD) for an appropriate treatment. A new route to obtain these doubly excited states using EOM-CCSD is demonstrated. Traditionally, EOM-CC is performed on a closed shell reference state that has a well-described single reference CC wavefunction. In this Communication, we attempt to use low spin open-shell states such as the MS = 0 triplet and open-shell singlet as a reference state. Using this intermediate excited state as a reference state provides us with the benefit of obtaining a doubly excited state, as a single excitation at the cost of EOM-CCSD.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 23, 2022
- Source ID
- 10.1063/5.0091715
Entities
People
- Ajith Perera
- Moneesha Ravi
- Rodney J. Bartlett
- Young Choon Park
Organizations
- Air Force Office of Scientific Research
- University of Florida