Use of semiempirical methods for the prediction of equilibrium geometries and ionization potentials of 4h-pyran-4-one and sulphur analogues

Árpád Somogyi, Zoltán Dinya, Attila Császár, Pál Császár

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Equilibrium geometries and ionization energies of 4H-pyran-4-one (I) 4H-pyran-4-thione (II), 4H-thiapyran-4-one (III) and 4H-thiapyran-4-thione (IV) are calculated by CNDO/2 and MINDO/3 semiempirical methods. The geometries obtained are compared to the MW data available for I, II and IV. Reliability of geometry optimization and predictions based on semiempirical results are discussed. For I the vertical ionization energies estimated from ab initio, CNDO/2 and MINDO/3 orbital energies are compared to each other and to those obtained by HAM/3 calculations. The HAM/3 results are in the best agreement with the experimental data. For systematic HAM/3 studies on molecules for which no experimental geometries are available, the use of CNDO/3 or MINDO/3 optimized geometries is suggested.

Original languageEnglish
Pages (from-to)95-104
Number of pages10
JournalJournal of Molecular Structure: THEOCHEM
Issue numberC
Publication statusPublished - Nov 1985


ASJC Scopus subject areas

  • Biochemistry
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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