Abstract

Different time-resolved spectroscopic techniques, both in the picosecond and sub-picosecond regimes have been used to investigate the photophysics of the isomerization reaction of the molecule 1,1‘-diethyl-4,4‘-cyanine (fig.1a). The molecule is characterized by a very short excited state lifetime with a linear viscosity dependence over a wide viscosity range and no, or a negative temperature dependence of the reaction rate [1]. We therefore believe that this molecule can be a representative of the barrierless reaction type (fig. 1a).

© 1992 The Author(s)