An electronegativity-induced spin repulsion effect

András Stirling, Alfredo Pasquarello

Research output: Contribution to journalArticle

2 Citations (Scopus)


We present a spin delocalization effect in radical Si-containing systems, featuring a heteroatom of high electronegativity (such as N, O, or Cl) bonded to the unsaturated Si atom. We find that the higher the electronegativity of the heteroatom, the more the localized spin shifts away from the unsaturated Si atom and the heteroatom toward saturated Si neighbors. We demonstrate that this spin repulsion toward saturated Si atoms is induced by the electronegativity difference between the Si atom and the heteroatoms. We present a simple molecular-orbital-based mechanism which fully explains the structural and electronic effects. We contrast the present spin delocalization mechanism with the classical hyperconjugation in organic chemistry. The most important consequences of this spin redistribution are the electron-spin-resonance activity of the saturated Si neighbors and the enhanced stability of the radical centers. We predict a similar effect for Ge radicals and discuss why organic systems based on carbon do not feature such spin repulsion.

Original languageEnglish
Pages (from-to)8385-8390
Number of pages6
JournalJournal of Physical Chemistry A
Issue number37
Publication statusPublished - Sep 22 2005

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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