Lee Richter's research interests lie in the application of optical diagnostics to the study of time-dependent processes occurring at interfaces. He has participated in a series of collaborative research studies that utilized state-resolved gas-phase diagnostics (both laser-induced fluorescence and resonance-enhanced multiphoton ionization) to characterized the energy disposal in the gas phase products arising from surface photochemical events, both photodissociation and photodesorption. These studies employed UHV techniques to prepare well-characterized initial surfaces, and have utilized both ns and fs laser sources to drive the photochemistry. He is currently active in the area of optical characterization of thin films and interfaces, specifically in the development of second-order nonlinear-optical techniques (second harmonic generation, SHG, and sum frequency generation, SFG) for the study of both carrier dynamics at buried interfaces (via electronically resonant SHG) and in situ molecular dynamics (via vibrationally resonant SFG).