Resonance Raman activity in odd quanta of the trans bending vibration of acetylene: Strong vibronic coupling in the X̃ to à and X̃ to B̃ transitions

Jerome Berryhill, Shekhar Pramanick, Marek Z. Zgierski, Francesco Zerbetto, Bruce S. Hudson

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Resonance Raman spectra of acetylene with excitation at 204 and 178 nm in the region X̃→Ã(1Σg1Σ-u in D∞h) and X̃→B̃(1Σ+g1Δu in D∞h) transitions exhibit very strong activity in both even and odd quanta of the πg(v4) trans bending vibration. Enhancement of the two-quantum even overtone is expected from linear vibronic activity in these forbidden transitions resulting in quadratic (C-term) Raman activitiy. The higher even quanta overtone activity is consistent with strongly bent excited states or nonlinear vibronic coupling. The induction of intensity in the odd overtones of this non-totally symmetric vibrational mode, however, requires mixed linear and quadratic vibronic coupling involving two different allowed excitations (to states of 1Πu and 1Σ+u symmetry).

Original languageEnglish (US)
Pages (from-to)39-45
Number of pages7
JournalChemical Physics Letters
Volume205
Issue number1
DOIs
StatePublished - Apr 2 1993

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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