PICOSECOND PHOTODISSOCIATION OF TETRAPHENYLHYDRAZINE

The photodissociation of tetraphenylhydrazine has been re-examined using picosecond transient absorption spectroscopy over a wider wavelength range than previously reported and also over a range of temperatures in isoviscous solution. An activation energy of 10.6 kJ mol-1 for dissociation from the excited singlet state is measured. an interpretation of the data consistent with the picosecond transients at all measured wavelengths is that the excited state decay is determined by photodissociation and not geminate recombination of the radicals. The photodissociation rate constants, measured in alkane solvents of differing viscosity, are described by Kramers' equation.