Evidence of the dynamic disordering effects in PICCl J-aggregates from picosecond spectroscopy

We employ a pump-probe approach to strongly excited molecular aggregates to study disordering processes. The experimental data obtained for PIC Cl J-a ggregates at room temperature are discussed on the basis of the theory, whi ch takes into account the effect of dynamic disordering in one-dimensional molecular systems. Experimentally measured features of the spectral positio n and magnitude of the difference absorption spectra are shown as appeared due to 'hot' processes of off-diagonal disordering of an excited aggregate after the annihilation event. (C) 2001 Elsevier Science B.V. All rights res erved.