Resonance Raman depolization ratios for cyclopentadiene demonstrate the presence of two overlapping electronic transitions with perpendicular polarizations in the low energy absorption band: the 1B2 and 2A1 states

Quan yuan Shang, Bruce S. Hudson

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The absorption spectrum of 1,3-cyclopentadiene in the 260-220 nm region exhibits some vibrational structure superimposed on a broad continuum. The depolarization ratios (p) of resonantly enhanced Raman transitions of the three strongest totally symmetric modes of vibration all deviate significantly from the value of 1 3 corresponding to a single electronic transition. This directly and unambiguously demonstrates the presence of two overlapping electronic transitions with perpendicular transition moments. The variation of p with excitation wavelength is consistent with association of the weak structured absorption with the transition to the 2A1 state, analogous to the 2Ag state of centrosymmetric polyenes, and the much stronger underlying continuous absorption with the transition to the 1B2 state, analogous to the corresponding 1Bu state of butadiene.

Original languageEnglish (US)
Pages (from-to)63-68
Number of pages6
JournalChemical Physics Letters
Volume183
Issue number1-2
DOIs
StatePublished - Aug 23 1991

ASJC Scopus subject areas

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

Fingerprint Dive into the research topics of 'Resonance Raman depolization ratios for cyclopentadiene demonstrate the presence of two overlapping electronic transitions with perpendicular polarizations in the low energy absorption band: the 1B<sub>2</sub> and 2A<sub>1</sub> states'. Together they form a unique fingerprint.

Cite this