Jacques Joussot-Dubien

Giant pulse laser photolysis of benzene and mesitylene

Abstract Using a flash photolysis apparatus in which the excitation was provided by a giant pulsed neodymium laser giving 100 mJ at 2645A after two frequency doublings, we have looked for transient absorptions in benzene and mesitylene dissolved in cyclohexane or ethanol. We have observed in the 4000–6000A range a transient absorption that we assign to a singlet * -singlet * transition ( 1 E 1u ← 1 B 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.

pH DEPENDENCE OF SENSITIZED PHOTOOXIDATION IN MICELLAR ANIONIC AND CATIONIC SURFACTANTS, USING THIAZINES DYES

Abstract— Our study of the kinetics of sensitized photooxidation, as a function of pH in anionic micellar systems using cationic dyes as sensitizers, shows that adsorption of the dye slows the protonation step of his triplet state. This observation has important implicaticins in interpretation of results in the so‐called photodynamic effect in biological systems: using cationic dyes as sensitizers the rate of photooxidation for the same pH is different depending whether or not the medium allows adsorption of the dye.

Photochemical reaction of anthracene in cyclohexane polycrystals dispersed in liquid nitrogen

U.v. photolysis of a polycrystalline solution of anthracene in cyclohexane at 77 K followed by separation of the stable photoproducts at room temperature, yielded 9,10-dihydroanthracene, 9-cyclohexyl-9,10-dihydroanthracene, 9-cyclohexylanthracene, and oxidized derivatives of anthracene.