Energy transfer diffusion effects

Other possible solvent effects depend on the heavy-atom effect, which may favor intersystem crossing, and on the viscosity, which may change the rate of diffusion and hence the collisional triplet-triplet energy transfer. These effects have already been mentioned in previous sections. 

Enhancement of surface diffusion of the growth precursors is considered as one of the beneficial effects of ion bombardment [246,428]. The potential energy of ions, which is released when the ion is neutralized, is typically 10 eV. This energy can be a substantial fraction of the total energy transferred. The release of this ionization energy is sufficient to excite atoms into excited electronic states, thereby weakening their bonds and enhancing their mobilities [429]. 

Figure 10.13. Dependence of energy transfer on concentration of Phenol Red, for the protonated (Roi = 28.3 A) and unprotonated form (R02 = 52.5 A). The inset shows the pH-dependent energy transfer using an acceptor concentration of 4 x 10 3 M (effect of diffusion is omitted).

Photochemistry in Modified Supercritical Carbon Dioxide—Effect of Modifier Concentration on Diffusion Probed by Triplet-Triplet Energy Transfer (Worrall and Wilkinson, 1996)... 

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