Many-Body Basis Set Amelioration Method for Incremental Full Configuration Interaction

Hatch, Jeffrey [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0009000791948786); Rask, Alan E. [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000224926962); Dang, Duy-Khoi [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000175300540); Zimmerman, Paul M. [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000274441314)

doi:10.1021/acs.jpca.5c01521

DOE OSTI · 2587304

Many-Body Basis Set Amelioration Method for Incremental Full Configuration Interaction

Hatch, Jeffrey [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0009000791948786)·Rask, Alan E. [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000224926962)·Dang, Duy-Khoi [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000175300540)·Zimmerman, Paul M. [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000274441314)

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Abstract

Incremental full configuration interaction (iFCI) is a polynomial-cost electronic structure method that systematically approaches the FCI limit by employing the method of increments to solve the Schrödinger equation through a many-body expansion. This article introduces the many-body basis set amelioration (MBBSA) method, which is designed to allow iFCI to be applicable to larger atomic orbital basis sets. MBBSA uses a series of inexpensive iFCI calculations to approximate the correlation energy that would be found using a more expensive, highly accurate iFCI calculation. Here, when compared to standard iFCI computations on smaller molecules in triple-zeta and larger basis sets, MBBSA provides approximations to the total and relative energies within chemical accuracy. MBBSA exhibits a reduced cost of between 60-92% when compared to standard iFCI calculations, with larger systems experiencing the largest benefit. Tests of MBBSA on two reactions that involve highly correlated systems, the automerization of cyclobutadiene and a Criegee intermediate reaction, show that MBBSA has practical utility for studying realistic chemistries.

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Hatch, Jeffrey [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0009000791948786), Rask, Alan E. [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000224926962), Dang, Duy-Khoi [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000175300540), Zimmerman, Paul M. [University of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000274441314). 2025-04-14. Many-Body Basis Set Amelioration Method for Incremental Full Configuration Interaction. https://doi.org/10.1021/acs.jpca.5c01521

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