title: Ultrafast spectroscopy of even-parity states in pi-conjugated polymers
abstract: 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 Planck's over 2piomega<1.1 eV ultrafast internal conversion back to 1 (1)B(u) takes place in accordance with Vavilov-Kasha's rule. However, for Planck's over 2piomega>1.1 eV the decay occurs in a nonemissive state identified as a polaron pair, showing that the A(g) states above 3.3 eV mediate charge transfer.
authors.affiliation: Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974, USA.
authors.initials: SV
authors.lastname: Frolov
authors.initials: Z
authors.lastname: Bao
authors.initials: M
authors.lastname: Wohlgenannt
authors.initials: ZV
authors.lastname: Vardeny