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Updated: Mar 26, 2026

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Published on: May 27, 2020
Multiconfiguration Pair-Density Functional Theory Is as Accurate as CASPT2 for Electronic Excitation
Chad E Hoyer1, Soumen Ghosh1, Donald G Truhlar1
1Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States.
Abstract:
A correct description of electronically excited states is critical to the interpretation of visible-ultraviolet spectra, photochemical reactions, and excited-state charge-transfer processes in chemical systems. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory and a new kind of density functional called an on-top density functional. Here, we show that MC-PDFT with a first-generation on-top density functional performs as well as CASPT2 for an organic chemistry database including valence, Rydberg, and charge-transfer excitations. The results are very encouraging for practical applications.
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