PlumX Metrics
Embed PlumX Metrics

Fractional spins and static correlation error in density functional theory

Journal of Chemical Physics, ISSN: 0021-9606, Vol: 129, Issue: 12, Page: 121104
2008
  • 226
    Citations
  • 0
    Usage
  • 201
    Captures
  • 0
    Mentions
  • 0
    Social Media
Metric Options:   Counts1 Year3 Year

Metrics Details

Article Description

Electronic states with fractional spins arise in systems with large static correlation (strongly correlated systems). Such fractional-spin states are shown to be ensembles of degenerate ground states with normal spins. It is proven here that the energy of the exact functional for fractional-spin states is a constant, equal to the energy of the comprising degenerate pure-spin states. Dramatic deviations from this exact constancy condition exist with all approximate functionals, leading to large static correlation errors for strongly correlated systems, such as chemical bond dissociation and band structure of Mott insulators. This is demonstrated with numerical calculations for several molecular systems. Approximating the constancy behavior for fractional spins should be a major aim in functional constructions and should open the frontier for density functional theory to describe strongly correlated systems. The key results are also shown to apply in reduced density-matrix functional theory. © 2008 American Institute of Physics.

Provide Feedback

Have ideas for a new metric? Would you like to see something else here?Let us know