ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The method of chemical timing for obtaining picosecond time-resolved fluorescence spectra has been applied to the measurement of intramolecular vibrational redistribution (IVR) in S1 p-difluorobenzene. In this report, a more detailed examination of the spectroscopy of some vibrationally mixed levels is used in conjunction with the previously measured IVR parameters to construct a generalized picture of the rovibronic level structure giving rise to IVR. Strong, off-resonance interactions are observed to mix levels separated by several cm−1, contributing additional discrete structure to the spectrum but not directly affecting the IVR dynamics. The dynamics, instead, reflect on-resonance interactions between levels separated only by a few tenths of a wave number that give rise to congested background emission. Evidence is seen in comparisons between bulb and jet spectra for the involvement of vibration-rotation coupling in both the off-resonance and the on-resonance interactions. A particularly important and subtle rotational effect is the change of the coupled vibrational field with rotational excitation due to the variation of rotational constants with vibrational excitation, leading to a smoother congested background.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.450553
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