Acenaphthylene, photosensitized

The evidence from photosensitization derives from the Rose Bengal (RB) sensitized dimerization of acenaphthylene.1 15 It is observed that one RB molecule can yield, by repeated excitation, dimeric molecules with a high conversion. This requires that dimers move away from the RB molecules and that monomers move to occupy these vacant places. Evidence has been presented1 that the RB molecules are firmly fixed to the surface and thus the acenaphthylene monomers and dimers must be undergoing extensive motion on the surface during... 

The importance of light absorption to directly populate the triplet state in the presence of heavy atoms [(10.271)] and the effect of heavy atoms on the phosphorescence of acenaphthylene [(10.27m)] are easily ruled out. No new absorption bands or increased band intensities are noted in the presence of heavy atoms. Since no phosphorescence is observed, even at low temperature, there cannot be an important effect on this process. A heavy-atom effect on the partitioning of reactions (10.27g,h) and (10.27k) is eliminated by the data of Hartmann, Hartmann, and Schenck in their study of solvent effects on the photosensitized photolysis of acenaphthylene. The influence of a number of solvents was described with the use of Kirkwood-Onsager solvent parameters (an empirical method for the correlation of reaction rate with the ability of the solvent to stabilize the change in dipole moment in proceeding to the transition state). A linear plot of log(fra/u/cw) vs. the expression [(Z) — 1)/(2Z) -f- where D is the dielectric constant, p is... 

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