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Title: Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems

Abstract

Predicting ground- and excited-state properties of open-shell organic molecules by electronic structure theory can be challenging because an accurate treatment has to correctly describe both static and dynamic electron correlation. Strongly correlated systems, i.e., systems with near-degeneracy correlation effects, are particularly troublesome. Multiconfigurational wave function methods based on an active space are adequate in principle, but it is impractical to capture most of the dynamic correlation in these methods for systems characterized by many active electrons. Here, we recently developed a new method called multiconfiguration pair-density functional theory (MC-PDFT), that combines the advantages of wave function theory and density functional theory to provide a more practical treatment of strongly correlated systems. Here we present calculations of the singlet–triplet gaps in oligoacenes ranging from naphthalene to dodecacene. Calculations were performed for unprecedently large orbitally optimized active spaces of 50 electrons in 50 orbitals, and we test a range of active spaces and active space partitions, including four kinds of frontier orbital partitions. We show that MC-PDFT can predict the singlet–triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MC-PDFT may constitute the benchmark against which those other models should be compared, given the absencemore » of experimental data.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry, Chemical Theory Center, Supercomputing Inst.
Publication Date:
Research Org.:
Univ. of Minnesota, Minneapolis, MN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1423814
Grant/Contract Number:
SC0008666
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 4; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Ghosh, Soumen, Cramer, Christopher J., Truhlar, Donald G., and Gagliardi, Laura. Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems. United States: N. p., 2017. Web. doi:10.1039/c6sc05036k.
Ghosh, Soumen, Cramer, Christopher J., Truhlar, Donald G., & Gagliardi, Laura. Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems. United States. doi:10.1039/c6sc05036k.
Ghosh, Soumen, Cramer, Christopher J., Truhlar, Donald G., and Gagliardi, Laura. Thu . "Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems". United States. doi:10.1039/c6sc05036k. https://www.osti.gov/servlets/purl/1423814.
@article{osti_1423814,
title = {Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems},
author = {Ghosh, Soumen and Cramer, Christopher J. and Truhlar, Donald G. and Gagliardi, Laura},
abstractNote = {Predicting ground- and excited-state properties of open-shell organic molecules by electronic structure theory can be challenging because an accurate treatment has to correctly describe both static and dynamic electron correlation. Strongly correlated systems, i.e., systems with near-degeneracy correlation effects, are particularly troublesome. Multiconfigurational wave function methods based on an active space are adequate in principle, but it is impractical to capture most of the dynamic correlation in these methods for systems characterized by many active electrons. Here, we recently developed a new method called multiconfiguration pair-density functional theory (MC-PDFT), that combines the advantages of wave function theory and density functional theory to provide a more practical treatment of strongly correlated systems. Here we present calculations of the singlet–triplet gaps in oligoacenes ranging from naphthalene to dodecacene. Calculations were performed for unprecedently large orbitally optimized active spaces of 50 electrons in 50 orbitals, and we test a range of active spaces and active space partitions, including four kinds of frontier orbital partitions. We show that MC-PDFT can predict the singlet–triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MC-PDFT may constitute the benchmark against which those other models should be compared, given the absence of experimental data.},
doi = {10.1039/c6sc05036k},
journal = {Chemical Science},
number = 4,
volume = 8,
place = {United States},
year = {Thu Jan 19 00:00:00 EST 2017},
month = {Thu Jan 19 00:00:00 EST 2017}
}

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Cited by: 7works
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  • Inspired by earlier work on the band-gap problem in insulators, we reexamine the treatment of strongly correlated Hubbard-type models within density-functional theory. In contrast to previous studies, the density is fully parametrized by occupation numbers {ital and} overlap of orbitals centered at neighboring atomic sites, as is the local potential by the hopping matrix. This corresponds to a good formal agreement between density-functional theory in real space and second quantization. It is shown that density-functional theory is formally applicable to such systems and the theoretical framework is provided. The question of noninteracting {ital v} representability is studied numerically for finitemore » one-dimnsional clusters, for which exact results are available, and qualitatively for infinite systems. This leads to the conclusion that the electron density corresponding to interacting systems of the type studied here is in fact {ital not} noninteracting {ital v} representable because the Kohn-Sham electrons are unable to reproduce the correlation-induced localization correctly.« less
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