@article{a1c3c33363cd4d9cb353a8a61c14ae1c,
title = "On the role of dynamic electron correlation in non-orthogonal configuration interaction with fragments",
abstract = "Two different approaches have been implemented to include the effect of dynamic electron correlation in the Non-Orthogonal Configuration Interaction for Fragments (NOCI-F) method. The first is based on shifting the diagonal matrix elements of the NOCI matrix, while the second incorporates the dynamic correlation explicitly in the fragment wave functions used to construct the many-electron basis functions of the NOCI. The two approaches are illustrated for the calculation of the electronic coupling relevant in singlet fission and the coupling of spin moments in organic radicals. Comparison of the calculated diabatic couplings, the NOCI energies and wave functions shows that dynamic electron correlation is not only efficiently but also effectively incorporated by the shifting approach and can largely affect the coupling between electronic states. Also, it brings the NOCI coupling of the spin moments in close agreement with benchmark calculations.",
author = "A. S{\'a}nchez-Mansilla and C. Sousa and Kathir, \{R. K.\} and R. Broer and Straatsma, \{T. P.\} and \{de Graaf\}, C.",
note = "Funding Information: This work used resources through the INCITE program of the Oak Ridge Leadership Computing Facility (OLCF) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. We acknowledge PRACE for awarding us access to JUWELS at GCS@FZJ, Germany. Financial support has been provided by the Spanish Ministerio de Ciencia Innovaci{\'o}n y Universidades (Projects RTI2018-095460-B-I00, CTQ2017-83566-P, PID2020-113187GB-I00 and the Excellence Mar{\'i}a de Maeztu grant MDM-2017-0767) and by the Generalitat de Catalunya (Projects 2017SGR13 and 2017-SGR629). This work is part of the research program “Computational sciences for energy research” (project 15CSER73), which is financed by the Dutch Research Council (NWO). The data that supports the findings of this study are available within the article and its supplementary material. This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( https://energy.gov/downloads/doe-public-access-plan ). Funding Information: This work used resources through the INCITE program of the Oak Ridge Leadership Computing Facility (OLCF) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. We acknowledge PRACE for awarding us access to JUWELS at GCS@FZJ, Germany. Financial support has been provided by the Spanish Ministerio de Ciencia Innovaci{\'o}n y Universidades (Projects RTI2018-095460-B-I00, CTQ2017-83566-P, PID2020-113187GB-I00 and the Excellence Mar{\'i}a de Maeztu grant MDM-2017-0767) and by the Generalitat de Catalunya (Projects 2017SGR13 and 2017-SGR629). This work is part of the research program “Computational sciences for energy research” (project 15CSER73), which is financed by the Dutch Research Council (NWO). The data that supports the findings of this study are available within the article and its supplementary material. This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (https://energy.gov/downloads/doe-public-access-plan). Publisher Copyright: {\textcopyright} 2022 The Royal Society of Chemistry",
year = "2022",
month = may,
day = "2",
doi = "10.1039/d2cp00772j",
language = "English",
volume = "24",
pages = "11931--11944",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "ROYAL SOC CHEMISTRY",
number = "19",
}