Giant pulse laser photolysis of benzene and mesitylene

Using a flash photolysm apparatus m which the excitation was provided by a giant pulsed neodymium laser giving 100 mJ at 2645 angstrom after two frequency doublmgs, we have looked for transient absorptions in benzene and mesitylene dissolved m cyclohexane or ethanol. We have observed, m the 4000-6000h range a transient absorption that we assign to a singlet*-singlet* transition (E-1(1u)<-- B-1(2u)). In addition, three other transients appear with lifetimes approximatively equal to 300 ns. 450 ns and few microseconds. Assignment of these three transients is tentatively discussed.