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Multiconfigurational short-range density-functional theory for open-shell systems

Hedegård, Erik Donovan LU ; Toulouse, Julien and Jensen, Hans Jørgen Aagaard (2018) In Journal of Chemical Physics 148(21).
Abstract

Many chemical systems cannot be described by quantum chemistry methods based on a single-reference wave function. Accurate predictions of energetic and spectroscopic properties require a delicate balance between describing the most important configurations (static correlation) and obtaining dynamical correlation efficiently. The former is most naturally done through a multiconfigurational (MC) wave function, whereas the latter can be done by, e.g., perturbation theory. We have employed a different strategy, namely, a hybrid between multiconfigurational wave functions and density-functional theory (DFT) based on range separation. The method is denoted by MC short-range DFT (MC-srDFT) and is more efficient than perturbative approaches as... (More)

Many chemical systems cannot be described by quantum chemistry methods based on a single-reference wave function. Accurate predictions of energetic and spectroscopic properties require a delicate balance between describing the most important configurations (static correlation) and obtaining dynamical correlation efficiently. The former is most naturally done through a multiconfigurational (MC) wave function, whereas the latter can be done by, e.g., perturbation theory. We have employed a different strategy, namely, a hybrid between multiconfigurational wave functions and density-functional theory (DFT) based on range separation. The method is denoted by MC short-range DFT (MC-srDFT) and is more efficient than perturbative approaches as it capitalizes on the efficient treatment of the (short-range) dynamical correlation by DFT approximations. In turn, the method also improves DFT with standard approximations through the ability of multiconfigurational wave functions to recover large parts of the static correlation. Until now, our implementation was restricted to closed-shell systems, and to lift this restriction, we present here the generalization of MC-srDFT to open-shell cases. The additional terms required to treat open-shell systems are derived and implemented in the DALTON program. This new method for open-shell systems is illustrated on dioxygen and [Fe(H2O)6]3+.

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author
organization
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type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Physics
volume
148
issue
21
publisher
American Institute of Physics
external identifiers
  • scopus:85048182179
ISSN
0021-9606
DOI
10.1063/1.5013306
language
English
LU publication?
yes
id
779bf421-1e61-4d9e-a6cf-1f5c186118ab
date added to LUP
2018-06-20 15:40:34
date last changed
2018-06-21 03:00:04
@article{779bf421-1e61-4d9e-a6cf-1f5c186118ab,
  abstract     = {<p>Many chemical systems cannot be described by quantum chemistry methods based on a single-reference wave function. Accurate predictions of energetic and spectroscopic properties require a delicate balance between describing the most important configurations (static correlation) and obtaining dynamical correlation efficiently. The former is most naturally done through a multiconfigurational (MC) wave function, whereas the latter can be done by, e.g., perturbation theory. We have employed a different strategy, namely, a hybrid between multiconfigurational wave functions and density-functional theory (DFT) based on range separation. The method is denoted by MC short-range DFT (MC-srDFT) and is more efficient than perturbative approaches as it capitalizes on the efficient treatment of the (short-range) dynamical correlation by DFT approximations. In turn, the method also improves DFT with standard approximations through the ability of multiconfigurational wave functions to recover large parts of the static correlation. Until now, our implementation was restricted to closed-shell systems, and to lift this restriction, we present here the generalization of MC-srDFT to open-shell cases. The additional terms required to treat open-shell systems are derived and implemented in the DALTON program. This new method for open-shell systems is illustrated on dioxygen and [Fe(H<sub>2</sub>O)<sub>6</sub>]<sup>3+</sup>.</p>},
  articleno    = {214103},
  author       = {Hedegård, Erik Donovan and Toulouse, Julien and Jensen, Hans Jørgen Aagaard},
  issn         = {0021-9606},
  language     = {eng},
  month        = {06},
  number       = {21},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Multiconfigurational short-range density-functional theory for open-shell systems},
  url          = {http://dx.doi.org/10.1063/1.5013306},
  volume       = {148},
  year         = {2018},
}