Systematic GVB study of harmonic vibrational frequencies and dipole moment derivatives; the vinyl radical C2H3 and other simple molecules

Michel Dupuis, J. J. Wendoloski

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Structure, harmonic vibrational frequencies, and dipole moment derivatives of methane, ethylene, and acetylene have been obtained from generalized valence bond (GVB) wave function calculations. The results are compared to Hartree-Fock (HF) data, and other correlated wave function data. It is found that the GVB method consistently overemphasizes left-right electron correlation effects, and predicts bond lengths ∼0.01-0.02 Å longer than experiment. However, the calculated harmonic frequencies are within 4.2% of the observed fundamentals and within 3.5% of the experimental harmonic frequencies. Dipole moment derivatives are in semi-quantitative agreement with experiment. The method is used to predict the IR spectrum of the vinyl radical, including a very intense out of plane bending mode with frequency near 1000 cm-1.

Original languageEnglish
Pages (from-to)5696-5702
Number of pages7
JournalJournal of Chemical Physics
Issue number11
Publication statusPublished - 1984


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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