Observation of the wave-packet oscillation during the exciton self-trapping process in a quasi-one-dimensional halogen-bridged Pt complex

Using femtosecond time-resolved luminescence spectroscopy, we have observed a wave-packet oscillation in an adiabatic potential well associated with a self-trapped exciton (STE). We have investigated the STE luminescence band of a quasi-one-dimensional halogen-bridged platinum complex [Pt(en)(2)][Pt (en)(2)Br-2](ClO4)(4). In the time evolution of the luminescence, we have o bserved an oscillation with a period of about 300 fs. This result shows the formation of a wave packet and its oscillation, which is damped with the t ime constant of about 430 fs. The STE's have a lifetime of about 5.5 ps at room temperature. [S0163-1829(99)06135-4].