Photochemistry is the study of chemical reactions that are initiated or controlled by light. This field of chemistry explores how light energy can be used to initiate or drive chemical reactions, leading to the formation of new molecules, compounds, or species. Photochemical reactions are an important area of research with applications in a wide range of fields, including organic synthesis, materials science, environmental chemistry, and photobiology. The study of photochemistry involves understanding the mechanisms by which light interacts with molecules and how this interaction influences the outcome of chemical reactions.