Local spin from strongly orthogonal geminal wavefunctions

Péter Jeszenszki, Vitaly Rassolov, Péter R. Surján, Ágnes Szabados

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15 Citations (Scopus)


Covalent bond dissociation is examined by three geminal-based theories. One approach (antisymmetrised product of strongly orthogonal geminals) assumes purely singlet geminals, while two others operate with mixtures of singlets and triplets (cf. restricted-unrestricted strongly orthogonal singlet-type geminals, hereafter RUSSG). The RUSSG is the wavefunction in the second method. It is spin contaminated. The spin contamination of RUSSG is projected out in a spin-purification step in the third method. Description of local (i.e. atomic) spin by geminal-based theories is examined. Prototype systems showing the deficiency of singlet coupling are taken as test cases. We find that the local spin of equilibrium structures is correctly described by purely singlet geminals. Triplet geminals are shown to be essential for the description of local spin when dissociating multiple bonds, or switching between two Lewis structures of the same molecule.

Original languageEnglish
Pages (from-to)249-259
Number of pages11
JournalMolecular Physics
Issue number3-4
Publication statusPublished - Feb 16 2015



  • geminal
  • local spin
  • singlet coupling
  • spin unrestricted
  • strong orthogonality

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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