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Main Authors: Priyadarsini, Swati S., Gururangan, Karthik, Piecuch, Piotr
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.11856
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author Priyadarsini, Swati S.
Gururangan, Karthik
Piecuch, Piotr
author_facet Priyadarsini, Swati S.
Gururangan, Karthik
Piecuch, Piotr
contents We extend the CIPSI-driven CC($P$;$Q$) methodology [K. Gururangan et al., J. Chem. Phys. 155 (2021) 174114], in which the leading higher-than-doubly excited determinants are identified using the selected configuration interaction (CI) approach abbreviated as CIPSI, to excited electronic states via the equation-of-motion (EOM) coupled-cluster (CC) formalism. By examining vertical excitations in CH+ at equilibrium and stretched geometries, adiabatic excitations in CH, and ground- and excited-state potential cuts of water, we demonstrate that the CIPSI-driven CC($P$;$Q$) method converges parent CC/EOMCC singles, doubles, and triples energetics from relatively inexpensive Hamiltonian diagonalizations in CI spaces smaller than the corresponding triples manifolds.
format Preprint
id arxiv_https___arxiv_org_abs_2601_11856
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Extension of the CIPSI-Driven CC($P$;$Q$) Approach to Excited Electronic States
Priyadarsini, Swati S.
Gururangan, Karthik
Piecuch, Piotr
Chemical Physics
We extend the CIPSI-driven CC($P$;$Q$) methodology [K. Gururangan et al., J. Chem. Phys. 155 (2021) 174114], in which the leading higher-than-doubly excited determinants are identified using the selected configuration interaction (CI) approach abbreviated as CIPSI, to excited electronic states via the equation-of-motion (EOM) coupled-cluster (CC) formalism. By examining vertical excitations in CH+ at equilibrium and stretched geometries, adiabatic excitations in CH, and ground- and excited-state potential cuts of water, we demonstrate that the CIPSI-driven CC($P$;$Q$) method converges parent CC/EOMCC singles, doubles, and triples energetics from relatively inexpensive Hamiltonian diagonalizations in CI spaces smaller than the corresponding triples manifolds.
title Extension of the CIPSI-Driven CC($P$;$Q$) Approach to Excited Electronic States
topic Chemical Physics
url https://arxiv.org/abs/2601.11856