Multi-reference Fock space coupled-cluster method in the intermediate Hamiltonian formulation for potential energy surfaces
Abstract
The effective and intermediate Hamiltonian multi-reference coupled-cluster (CC) method with singles and doubles for the doubly ionized (0,2) sector of Fock space (FS) is formulated and implemented. The intermediate Hamiltonian realization of the (0,2) FS problem provides a robust computational scheme for solving the FS-CC equations free from the intruder state problem. By introducing an efficient factorization strategy, we obtain a very efficient tool that can be used for computing double ionization potentials but more significantly to describe multi-reference problems in CC theory, illustrated by twisted ethylene and the potential energy curve for F2. The latter separates smoothly to two F atoms, while the former avoids the cusp behavior at the 90° dihedral. We also explore the double ionization potentials for several small molecules, H2O, CO, C2H2, and C2H4.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 28, 2011
- Source ID
- 10.1063/1.3615500
Entities
People
- Monika Musiał
- Rodney J. Bartlett
Organizations
- Air Force Office of Scientific Research
- University of Florida
- University of Silesia in Katowice