Gradients for the partitioned equation-of-motion coupled-cluster method
- Univ. of Florida, Gainesville, FL (United States)
The Equation-of-Motion Coupled-Cluster method restricted to singles and doubles (EOM-CCSD) is a highly accurate method for calculating excited states of molecules. Errors of 0.1 to 0.3 eV are typical for excitation energies. But a major drawback is that EOM-CCSD is an iterative n{sup 6} method, and for large cases the cost can be prohibitive. For a partitioned EOM-CCSD calculation, the doubles-doubles block of the H matrix is replaced with Ho. Combined with truncating the H matrix at second order (i.e. basing the excited state calculation on a MBPT(2) ground state), the partitioning technique creates an iterative n{sup 5} method for excited states, the P-EOM-MBPT(2) method. In this poster we will present the theory and examples of P-EOM-MBPT(2) gradient calculations. The gradients provide an inexpensive way to look at potential energy surfaces of excited states of molecules.
- OSTI ID:
- 447559
- Report Number(s):
- CONF-960343-; TRN: 97:005456
- Resource Relation:
- Conference: 2. international congress on theoretical chemical physics, New Orleans, LA (United States), 9-13 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of Second international congress on theoretical chemical physics - ICTCP II; PB: 90 p.
- Country of Publication:
- United States
- Language:
- English
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