Igor V. RUBSTOV (IMS and JAIST) and Keitaro YOSHIHARA (IMS and JAIST)
[J. Phys. Chem. 101, 6138 (1997)]
We observed an oscillatory fluorescence decay dynamics of electron-donor-acceptor complex of hexamethylbenzene and tetracyanoethylene in CCl4 at room temperature. A fast spontaneous fluorescence decay with a characteristic time of 105 ± 20 fs was measured (Figure 1). An under-damped oscillation of fluorescence is overlapped with this fast decay. The period of the oscillation is 209 ± 4 fs which corresponds to a frequency of 159 ± 3 cm-1. The oscillation is tentatively assigned to an intermolecular vibration in the excited state. The damping time of the oscillations is 280 ± 30 fs.
Figure 1. Fluorescence decay observed at 777 nm. The best fit which includes sinusoidal part is shown. The oscillatory part is also shown separately.