Dispersed fs-FWM for Investigations of Low Frequency Vibrations of Transient Species in Combustion

Authors

  • Gregor Knopp Paul Scherrer Institute, General Energy Department, CH-5232 Villigen;, Email: gregor.knopp@psi.ch
  • Peter P. Radi Paul Scherrer Institute, General Energy Department, CH-5232 Villigen
  • Thomas Gerber Paul Scherrer Institute, General Energy Department, CH-5232 Villigen

DOI:

https://doi.org/10.2533/chimia.2011.339

Keywords:

Four-wave mixing, Low frequency vibrations, Peroxides, Time- and frequency resolved

Abstract

Understanding the role of peroxides in combustion, in atmospheric and in surface science involves investigations on a molecular level, at which energy transfers and rearrangements of the nuclei dictate the chemistry. Due to their high reactivity they appear as unstable transient species, which impedes detailed spectroscopic investigations. Low frequency modes, especially internal and hindered rotations with energies less than 200 cm-1 play an important role for the determination of molecular energies and reaction rates. Unfortunately, these motions are in general difficult to address. Femtosecond four-wave mixing (fs-FWM) is a powerful tool that allows for investigations of ground state dynamics of molecules. The high peak-power output of fs-lasers, facilitates the excitation of weak Raman coherences. Results from the combustion relevant di-tert-butyl peroxide molecule are exemplified.

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Published

2011-05-26

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