Ultrafast relaxation processes of the photoexcited states in MX-chains

Femtosecond transient absorption spectra of a quasi-one-dimensional halogen-bridged mixed-valence metal complex [Pt(en) 2 ][Pt(en) 2 Cl 2 ](PF 6 ) 4 have been measured. It has been found that the neutral solitons are generated from charge transfer excitons within the time resoution (300fsec). It is found that charged solitons are generated by the interband excitation. The rise time and decay time of the charged soliton absorption band are 2.2psec and 6.5psec respectively.