Brennan, John D.
Leigh, William J.
Photochemistry, or the chemistry of electronically excited states, deals with the behaviour of molecules upon absorption of light. Practical applications of research in this area abound in everyday life, from the natural processes of plant growth, vision or bioluminescence to artificial ones such as photography or xerography. At McMaster we deal with fundamental as well as applied aspects of mechanistic organic photochemistry, using state-of-the-art facilities for absorption and emission spectroscopy, nanosecond laser flash photolysis, and routine photochemical work in the gas, solution, or solid phases. McMaster is the home of pioneering studies of the photochemistry of carbenium ions, and current research in photochemical pericyclic reactions at McMaster is reshaping the application of orbital symmetry selection rules to excited state reactions. In other work we use well-characterized photochemical reactions or excited state processes to probe the effects of organized media such as liquid crystals, inclusion compounds, and micelles on molecular mobility, or to design special materials such as piezodialysis membranes.