Relaxation dynamics of even parity (A g ) states in poly( p-phenylene vinylene) derivatives are studied using a novel fsec transient spectroscopy, in which two different excitation pulses successively generate odd parity (1 1 B u ) excitons at 2.2 eV and then reexcite them to higher A g states. For reexcitation energies hv , 1.1 eV ultrafast internal conversion back to 1 1 B u takes place in accordance with Vavilov-Kasha's rule. However, forhv . 1.1 eV the decay occurs in a nonemissive state

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... ntified as a polaron pair, showing that the A g states above 3.3 eV mediate charge transfer.