Double ionization potential equation-of-motion coupled-cluster approach with full inclusion of 4-hole–2-particle excitations and three-body clusters
Year: 2025
Type: article
Abstract: The double ionization potential (DIP) equation-of-motion (EOM) coupled-cluster (CC) method with a full treatment of 4-hole-2-particle (4h-2p) correlations and triply excited clusters, abbreviated as DIP-EOMCCSDT(4h-2p), and its approximate form called DIP-EOMCCSD(T)(a)(4h-2p) have been formulated and implemented in the open-source CCpy package available on GitHub. The resulting codes work with both nonrelativistic and spin-free scalar-relativistic Hamiltonians. By examining the DIPs of a few small molecules, for which accurate reference data are available, we demonstrate that the DIP-EOMCCSDT(4h-2p) and DIP-EOMCCSD(T)(a)(4h-2p) approaches improve the results obtained using the DIP-EOMCC methods truncated at 3h-1p or 4h-2p excitations on top of the CC calculations with singles and doubles.
Source: The Journal of Chemical Physics
DOI: 10.1063/5.0253059
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: NEW SINGLE-AND MULTI-REFERENCE COUPLED-CLUSTER METHODS FOR HIGH ACCURACY CALCULATIONS OF . . ., G222768804, G4679419375, NEW COUPLED CLUSTER METHODS FOR MOLECULAR POTENTIAL ENERGY SURFACES, G5648016710, G6607271308, NEW SINGLE-AND MULTI-REFERENCE COUPLED-CLUSTER METHODS FOR HIGH ACCURACY CALCULATIONS OF . . ., G8682523248
OpenAlex ID: W4407339727