The origin of the problems with the PM3 core repulsion function

Gábor I. Csonka, János G. Ángyán

Research output: Contribution to journalArticle

81 Citations (Scopus)


We investigate the cause of failures of PM3 for H⋯H, O⋯H and N⋯H interactions. We show that the actual choice of parameters for the Gaussian correction functions leads to spurious oscillations in the interatomic core repulsion functions and in the potential energy surfaces. The positions of the minima of the Gaussian correction functions considerably influence the positions of the minima on the potential energy hypersurface of weak interactions. The PM3 potential energy curve of water dimer as a function of the O⋯H distance clearly illustrates the problem. The minimum at 1.8 Å and the wide shoulder at 2.1 Å correspond to a minimum and a maximum of the O⋯H Gaussian correction function, respectively.

Original languageEnglish
Pages (from-to)31-38
Number of pages8
JournalJournal of Molecular Structure: THEOCHEM
Issue number1-3 SPEC. ISS.
Publication statusPublished - Apr 21 1997


  • Core repulsion function
  • PM3

ASJC Scopus subject areas

  • Biochemistry
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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