Theoretical understanding of surface chemistry will eventually become a tool to design new chemical technology including: heterogeneous (photo) catalysts, photovoltaics, fuel cells and much more. To reach this goal, we require new ideas and new theories of molecular interactions at interfaces. Applying cutting-edge laser, molecular beam, and ultrahigh vacuum technology to design well-defined experiments that can catch molecules in the act of reacting, our group strives to provide benchmark measurements which set standards for the next generation of theoretical advance. In particular, we seek to discover the "rules" that govern the conversion of energy at interfaces. Although too small to see with the naked eye and too fast to follow except with the fastest pulsed lasers, energy conversion takes place one molecule at a time and one collision at a time. By isolating these individual energy conversion events and studying them, we are building the conceptual bridge connecting our macroscopic experience of energy conversion to the molecular world.