In addition to the TD-prompt component that can be fit with a MB distribution, long (slow) tails were seen in the TOF distributions of O and CO (see Figures and) that could not be solely captured by a MB fit. With tzero defined as the moment when the peak of a beam pulse strikes the surface, a thermal event in the microstructure that roughly occurs over timescales greater than 112 µs (see Supplementary Material for discussion) would appear slower in these TOF distributions. This was seen in vitreous carbon for CO , and an exponential decay fit was used to determine lifetimes of these slow processes. We extended this approach to obtain decay rate constants and flux components of processes occurring at long times. This method was suggested by Nathanson and co-workers to capture desorption events occurring over long times in molecular beam scattering from liquid surfaces .