ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The time dependence of fluorescence polarization has been measured for several vibronic levels of S1 pyrimidine, 000 pyrazine, and 000 5-methylpyrimidine in the collision-free environment of a supersonic jet. In each case, the polarization decreases from the regular-rotor-limit value to a smaller constant value. The decay of the polarization occurs with a rate smaller than that of the fast-component fluorescence but larger than that of the slow-component emission. The decay rate of the fluorescence polarization increases with increasing density of triplet rovibronic levels coupled to the initially prepared S1 state. The results are interpreted as providing evidence for vibration–rotation interactions in the triplet manifold, leading to an extensive, but incomplete, K mixing. The time scale of the rotational dynamics is proposed to be in the tens of nanoseconds, based on the decay of the fluorescence polarization.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.452721
