A challenge for density functionals: Self-interaction error increases for systems with a noninteger number of electrons

Yingkai Zhang, Weitao Yang

Research output: Contribution to journalArticlepeer-review

Abstract

The difficulty of widely used density functionals in describing the dissociation behavior of some homonuclear and heteronuclear diatomic radicals is analyzed. It is shown that the self-interaction error of these functionals accounts for the problem - it is much larger for a system with a noninteger number of electrons than a system with an integer number of electrons. We find the condition for the erroneous dissociation behavior described by approximate density functionals: when the ionization energy of one dissociation partner differs from the electron affinity of the other partner by a small amount, the self-interaction error will lead to wrong dissociation limit. Systems with a noninteger number of electrons and hence the large amount of self-interaction error in approximate density functionals arise also in the transition states of some chemical reactions and in some charge-transfer complexes. In the course of analysis, we derive a scaling relation necessary for an exchange-correlation functional to be self-interaction free.

Original languageEnglish (US)
Pages (from-to)2604-2608
Number of pages5
JournalJournal of Chemical Physics
Volume109
Issue number7
DOIs
StatePublished - 1998

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'A challenge for density functionals: Self-interaction error increases for systems with a noninteger number of electrons'. Together they form a unique fingerprint.

Cite this