Ultrafast vibrational population transfer dynamics in 2- acetylcyclopentanone studied by 2D IR spectroscopy

Sungnam Park, Minbiao Ji

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

2-Acetylcyclopentanone (2-ACP), which is a β-dicarbonyl compound, undergoes keto-enol isomerization, and its enol tautomers are stabilized by a cyclic intramolecular hydrogen bond. 2-ACP (keto form) has symmetric and asymmetric vibrational modes of the two carbonyl groups at 1748 and 1715 cm -1, respectively, which are well separated from the carbonyl modes of its enol tautomers in the FTIR spectrum. We have investigated 2-ACP dissolved in carbon tetrachloride by 2D IR spectroscopy and IR pump-probe spectroscopy. Vibrational population transfer dynamics between the two carbonyl modes were observed by 2D IR spectroscopy. To extract the population exchange dynamics (i.e., the down- and uphill population transfer rate constants), we used the normalized volumes of the cross-peaks with respect to the diagonal peaks at the same emission frequency and the survival and conditional probability functions. As expected, the downhill population transfer time constant (3.2 ps) was measured to be smaller than the uphill population transfer time constant (3.8 ps). In addition, the vibrational population relaxation dynamics of the two carbonyl modes were observed to be the same within the experimental error and were found to be much slower than vibrational population transfer between two carbonyl modes.

Original languageEnglish
Pages (from-to)799-805
Number of pages7
JournalChemPhysChem
Volume12
Issue number4
DOIs
Publication statusPublished - 2011 Mar 14

Keywords

  • 2D IR spectroscopy
  • coupled anharmonic oscillator
  • density functional calculations
  • population transfer dynamics
  • time-resolved spectroscopy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry

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