Finite size effects on aluminum/Teflon reaction channels under combustive environment: A Rice-Ramsperger-Kassel-Marcus and transition state theory study of fluorination Abstract. Three experimental techniques have been used to investigate the impact ignition of reactive materials. The three techniques are direct impact, indirect impact, and two-step impact. For the first two techniques, time-resolved light spectroscopy was used to identify reaction species from solid PTFE/Al reactive material. A common observation for these two techniques is that heating and some reaction was observed during initial impact of the PTFE/Al reactive material but the majority of the reaction appeared to occur following material breakup and subsequent impact with a secondary surface. There was no spectral evidence for aluminum-fluorine combustion. For the two-step impact technique, the reactive material was initially pulverized as it passed through a thin plate and then subsequently ignited when the debris cloud impacted a rigid anvil. All three experiments were observed with high-speed photography.