Molecular mechanisms of photosensitization.

Summary The first part of this article is devoted to basic concepts of photosensitization and to the primary photophysical and photochemistry processes involved in the reaction. The electronic configuration of molecular oxygen in its ground or activated states, which intervene in numerous photosensitized reactions, is reviewed. Finally, the main photosensitized reactions are reviewed and classified into three different groups: reactions due to radicals (type I), reactions due to singlet oxygen (type II) and those which do not involve oxygen (type III).