2025/02/21 by Jeffrey Hatch, Hatch, Jeffrey, Paul M. Zimmerman +1 · 1 voice · 1 citation
Computer Science · Physics and Astronomy · #Advanced Database Systems and Queries #Chemical Physics (physics.chem-ph) #Distributed and Parallel Computing Systems #FOS: Physical sciences #Service-Oriented Architecture and Web Services #physics.chem-ph
paper · pdf · doi:10.48550/arxiv.2502.15970
openalex publication_date 2025/02/21 · arxiv published 2025/02/21 · arxiv updated 2025/02/25 · openalex created_date 2025/10/15 · openalex updated_date 2026/07/28
Incremental full configuration interaction (iFCI) closely approximates the FCI limit with polynomial cost through a many-body expansion of the correlation energy, providing highly accurate total energies within a given basis set. To extend iFCI beyond previous basis set limitations, this work introduces a novel natural orbital screening approach, iNO-FCI. By consideration of the importance of virtual orbital selection in the convergence of iFCI, iNO-FCI maximizes the consistency between orbitals selected for each correlated body. iNO-FCI employs a principle of cancellation of errors and ensures that the same set of virtual NOs are used for interdependent terms. This strategy significantly reduces computational cost without compromises in precision. Computational savings of up to 95 percent are demonstrated, allowing access to larger basis sets that were previously computationally prohibitive. iNO-FCI is herein introduced and benchmarked for several difficult test cases involving double-bond dissociation, biradical systems, conjugated π systems, and the spin gap of a Cu-based transition metal complex.