Generalizedactivespace pairdensity functional theory: an efficient method to study large, strongly correlated, conjugated systems
Predicting ground and excitedstate properties of openshell 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 neardegeneracy 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 pairdensity functional theory (MCPDFT), 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 MCPDFT can predict the singlet–triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MCPDFT may constitute the benchmark against which those other models should be compared, given the absencemore »
 Authors:

^{[1]}
;
^{[1]}
;
^{[1]}
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 Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry, Chemical Theory Center, Supercomputing Inst.
 Publication Date:
 Grant/Contract Number:
 SC0008666
 Type:
 Accepted Manuscript
 Journal Name:
 Chemical Science
 Additional Journal Information:
 Journal Volume: 8; Journal Issue: 4; Journal ID: ISSN 20416520
 Publisher:
 Royal Society of Chemistry
 Research Org:
 Univ. of Minnesota, Minneapolis, MN (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC22)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
 OSTI Identifier:
 1423814
Ghosh, Soumen, Cramer, Christopher J., Truhlar, Donald G., and Gagliardi, Laura. Generalizedactivespace pairdensity functional theory: an efficient method to study large, strongly correlated, conjugated systems. United States: N. p.,
Web. doi:10.1039/c6sc05036k.
Ghosh, Soumen, Cramer, Christopher J., Truhlar, Donald G., & Gagliardi, Laura. Generalizedactivespace pairdensity 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. 2017.
"Generalizedactivespace pairdensity 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 = {Generalizedactivespace pairdensity 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 excitedstate properties of openshell 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 neardegeneracy 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 pairdensity functional theory (MCPDFT), 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 MCPDFT can predict the singlet–triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MCPDFT 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 = {2017},
month = {1}
}
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