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Spin Contamination in Inorganic Chemistry Calculations

  1. Jason L. Sonnenberg1,
  2. H. Bernhard Schlegel1,
  3. Hrant P. Hratchian2

Published Online: 15 SEP 2009

DOI: 10.1002/0470862106.ia617

Encyclopedia of Inorganic Chemistry

Encyclopedia of Inorganic Chemistry

How to Cite

Sonnenberg, J. L., Schlegel, H. B. and Hratchian, H. P. 2009. Spin Contamination in Inorganic Chemistry Calculations. Encyclopedia of Inorganic Chemistry. .

Author Information

  1. 1

    Wayne State University, Detroit, MI, USA

  2. 2

    Gaussian Inc., Wallingford, CT, USA

Publication History

  1. Published Online: 15 SEP 2009


An overview of spin contamination and its relationship to broken-symmetry wave functions are presented. Spin operator expectation-value formulas are developed for use with generalized, unrestricted, and restricted spin orbitals. Current projection techniques are reviewed and illustrated for a variety of current theoretical methods.


  • electronic structure;
  • Hamiltonian;
  • instability;
  • molecular orbital;
  • projection operators;
  • single reference;
  • spin;
  • stability;
  • symmetry breaking