Real-time picosecond clocking of the collision complex in a bimolecular reaction: The birth of OH from H+CO2

Picosecond (and femtosecond) photofragment spectroscopy has recently provided time-resolved, state-to-state dynamics of molecular photofragmentation. The focus of these experiments was on unimolecular reactions, where two main issues are fundamental to the dynamics: the nature of the "half-collision" and the degree to which statistical theories account for the time evolution of product state distributions (PSDs).