Theoretical equilibrium geometry, vibrational frequencies and the first electronic transition energy of HCC

G. Fogarasi, James E. Boggs, Péter Pulay

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Ab initio calculations with the 6-311 G** basis set and all single and double excitations in the CI treatment have been carried out to determine the structure of the HCC radical. The theoretical geometry of R(CC) = 1-209, r(CH) = 1-067 Å (or 1-205 and 1-063, respectively, if corrected for residual errors) is in excellent accordance with the experimental rotational constant. The calculated harmonic vibrational frequencies are v13450, v2 — 540 and v3 ~2040 cm-1. An extremely low energy around 2000 cm-1 is obtained for the first electronic transition A 3∏ ←X2Σ. Results for the excited state are also given. The theoretical vibrational frequencies, with all possible errors taken into account, are inconsistent with the accepted interpretations of the few experimental results. It is shown, however, that a complete reinterpretation of the spectroscopic observations is possible, by which the present calculations fit with the recent gas phase infrared laser spectroscopic data but remain in definite contradiction with the infrared matrix results.

Original languageEnglish
Pages (from-to)139-151
Number of pages13
JournalMolecular Physics
Volume50
Issue number1
DOIs
Publication statusPublished - 1983

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Vibrational spectra
Lasers
Gases
Geometry
Infrared lasers
Electron transitions
geometry
electronics
Excited states
infrared lasers
excitation
methylidyne
vapor phases
Infrared radiation
harmonics
energy
matrices

ASJC Scopus subject areas

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

Cite this

Theoretical equilibrium geometry, vibrational frequencies and the first electronic transition energy of HCC. / Fogarasi, G.; Boggs, James E.; Pulay, Péter.

In: Molecular Physics, Vol. 50, No. 1, 1983, p. 139-151.

Research output: Contribution to journalArticle

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