Other subjects explored include hydrogen bonding effects on the photochemistry of chromophores in solution, photochemical generation of silicon-centered radicals and their reactions, and photochemical processes at the air-water interface of atmospheric droplets.
Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class of psychoactive drugs. It is the world's most widely consumed psychoactive drug, but unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world.
Sources. Caffeine is a plant alkaloid, found in numerous plant species, where it acts as a natural pesticide that paralyzes and kills certain insects feeding upon them. The most commonly used caffeine-containing plants are coffee, tea, and to some extent cocoa.