Skip to main content
Journal cover image

Singlet-triplet energy gaps for diradicals from particle-particle random phase approximation.

Publication ,  Journal Article
Yang, Y; Peng, D; Davidson, ER; Yang, W
Published in: The journal of physical chemistry. A
May 2015

The particle-particle random phase approximation (pp-RPA) for calculating excitation energies has been applied to diradical systems. With pp-RPA, the two nonbonding electrons are treated in a subspace configuration interaction fashion while the remaining part is described by density functional theory (DFT). The vertical or adiabatic singlet-triplet energy gaps for a variety of categories of diradicals, including diatomic diradicals, carbene-like diradicals, disjoint diradicals, four-π-electron diradicals, and benzynes are calculated. Except for some excitations in four-π-electron diradicals, where four-electron correlation may play an important role, the singlet-triplet gaps are generally well predicted by pp-RPA. With a relatively low O(r(4)) scaling, the pp-RPA with DFT references outperforms spin-flip configuration interaction singles. It is similar to or better than the (variational) fractional-spin method. For small diradicals such as diatomic and carbene-like ones, the error of pp-RPA is slightly larger than noncollinear spin-flip time-dependent density functional theory (NC-SF-TDDFT) with LDA or PBE functional. However, for disjoint diradicals and benzynes, the pp-RPA performs much better and is comparable to NC-SF-TDDFT with long-range corrected ωPBEh functional and spin-flip configuration interaction singles with perturbative doubles (SF-CIS(D)). In particular, with a correct asymptotic behavior and being almost free from static correlation error, the pp-RPA with DFT references can well describe the challenging ground state and charge transfer excitations of disjoint diradicals in which almost all other DFT-based methods fail. Therefore, the pp-RPA could be a promising theoretical method for general diradical problems.

Duke Scholars

Altmetric Attention Stats
Dimensions Citation Stats

Published In

The journal of physical chemistry. A

DOI

EISSN

1520-5215

ISSN

1089-5639

Publication Date

May 2015

Volume

119

Issue

20

Start / End Page

4923 / 4932

Related Subject Headings

  • 5102 Atomic, molecular and optical physics
  • 3407 Theoretical and computational chemistry
  • 3406 Physical chemistry
  • 0307 Theoretical and Computational Chemistry
  • 0306 Physical Chemistry (incl. Structural)
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Yang, Y., Peng, D., Davidson, E. R., & Yang, W. (2015). Singlet-triplet energy gaps for diradicals from particle-particle random phase approximation. The Journal of Physical Chemistry. A, 119(20), 4923–4932. https://doi.org/10.1021/jp512727a
Yang, Yang, Degao Peng, Ernest R. Davidson, and Weitao Yang. “Singlet-triplet energy gaps for diradicals from particle-particle random phase approximation.The Journal of Physical Chemistry. A 119, no. 20 (May 2015): 4923–32. https://doi.org/10.1021/jp512727a.
Yang Y, Peng D, Davidson ER, Yang W. Singlet-triplet energy gaps for diradicals from particle-particle random phase approximation. The journal of physical chemistry A. 2015 May;119(20):4923–32.
Yang, Yang, et al. “Singlet-triplet energy gaps for diradicals from particle-particle random phase approximation.The Journal of Physical Chemistry. A, vol. 119, no. 20, May 2015, pp. 4923–32. Epmc, doi:10.1021/jp512727a.
Yang Y, Peng D, Davidson ER, Yang W. Singlet-triplet energy gaps for diradicals from particle-particle random phase approximation. The journal of physical chemistry A. 2015 May;119(20):4923–4932.
Journal cover image

Published In

The journal of physical chemistry. A

DOI

EISSN

1520-5215

ISSN

1089-5639

Publication Date

May 2015

Volume

119

Issue

20

Start / End Page

4923 / 4932

Related Subject Headings

  • 5102 Atomic, molecular and optical physics
  • 3407 Theoretical and computational chemistry
  • 3406 Physical chemistry
  • 0307 Theoretical and Computational Chemistry
  • 0306 Physical Chemistry (incl. Structural)
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics