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Multiconfigurational Pair-Density Functional Theory Is More Complex than You May Think

Rodrigues, Gabriel L.S. LU ; Scott, Mikael LU and Delcey, Mickael G. LU orcid (2023) In Journal of Physical Chemistry A 127(44). p.9381-9388
Abstract

Multiconfigurational pair-density functional theory (MC-PDFT) is a promising way to describe both strong and dynamic correlations in an inexpensive way. The functionals in MC-PDFT are often “translated” from standard spin density functionals. However, these translated functionals can in principle lead to “translated spin densities” with a nonzero imaginary component. Current developments so far neglect this imaginary part by simply setting it to zero. In this work, we show how this imaginary component is actually needed to reproduce the correct physical behavior in a range of cases, especially low-spin open shells. We showcase the resulting formalism on both local density approximation and generalized gradient approximation functionals... (More)

Multiconfigurational pair-density functional theory (MC-PDFT) is a promising way to describe both strong and dynamic correlations in an inexpensive way. The functionals in MC-PDFT are often “translated” from standard spin density functionals. However, these translated functionals can in principle lead to “translated spin densities” with a nonzero imaginary component. Current developments so far neglect this imaginary part by simply setting it to zero. In this work, we show how this imaginary component is actually needed to reproduce the correct physical behavior in a range of cases, especially low-spin open shells. We showcase the resulting formalism on both local density approximation and generalized gradient approximation functionals and illustrate the numerical behavior by benchmarking a number of singlet-triplet splittings (ST gaps) of organic diradicals and low-lying excited states of some common organic molecules. The results demonstrate that this scheme improves existing translated functionals and gives more accurate results, even with minimal active spaces.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry A
volume
127
issue
44
pages
8 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:37889622
  • scopus:85177875397
ISSN
1089-5639
DOI
10.1021/acs.jpca.3c05663
language
English
LU publication?
yes
additional info
Funding Information: The work was enabled by funding from VR project grant no. 2020-04639, Carl Tryggers stiftelse för vetenskaplig forskning, grant CTS 21:1462, and Olle Engkvists Stiftelse 214-0366. Computational resources from the Swedish National Infrastructure for Computing (SNIC) and the National Academic Infrastructure for Supercomputing in Sweden (NAISS) are also acknowledged. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.
id
42e3b731-5b22-488a-8241-879475f91b33
date added to LUP
2024-01-02 13:39:46
date last changed
2024-04-17 12:54:04
@article{42e3b731-5b22-488a-8241-879475f91b33,
  abstract     = {{<p>Multiconfigurational pair-density functional theory (MC-PDFT) is a promising way to describe both strong and dynamic correlations in an inexpensive way. The functionals in MC-PDFT are often “translated” from standard spin density functionals. However, these translated functionals can in principle lead to “translated spin densities” with a nonzero imaginary component. Current developments so far neglect this imaginary part by simply setting it to zero. In this work, we show how this imaginary component is actually needed to reproduce the correct physical behavior in a range of cases, especially low-spin open shells. We showcase the resulting formalism on both local density approximation and generalized gradient approximation functionals and illustrate the numerical behavior by benchmarking a number of singlet-triplet splittings (ST gaps) of organic diradicals and low-lying excited states of some common organic molecules. The results demonstrate that this scheme improves existing translated functionals and gives more accurate results, even with minimal active spaces.</p>}},
  author       = {{Rodrigues, Gabriel L.S. and Scott, Mikael and Delcey, Mickael G.}},
  issn         = {{1089-5639}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{44}},
  pages        = {{9381--9388}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry A}},
  title        = {{Multiconfigurational Pair-Density Functional Theory Is More Complex than You May Think}},
  url          = {{http://dx.doi.org/10.1021/acs.jpca.3c05663}},
  doi          = {{10.1021/acs.jpca.3c05663}},
  volume       = {{127}},
  year         = {{2023}},
}