Most chemical processes follow the Born-Oppenheimer (adiabatic) approximation, in which the nuclei move on a single electronic potential energy surface (PES). However there are important processes where this approximation breaks down. These nonadiabatic events play an important role in essential processes in nature such as photosynthesis, vision, charge transfer and photochemistry. Nonadiabatic processes are facilitated by the close proximity of two PES and the efficiency increases in the extreme case when two PES become degenerate forming conical intersections. Theoretical developments have enabled the efficient study of conical intersections in small systems. The focus of our group is to extend these studies to more complicated systems, particularly of biological interest, in an effort to understand the underlying mechanisms of photoinitiated nonadiabatic processes and their potential implications.