Despite this major disruption of the NP surface in Fig. , the NP remained inert to O2 after re-cooling to 1200 K. In this experiment, flash heating and subsequent cooling was done in argon, with O2 reactivity probed after a period of 1200 K storage in argon. To test the possibility that an inert NP might briefly become O2-reactive after a heating flash, a similar experiment was done in which the NP was held under oxidizing conditions during the flash heating/cooling periods (Fig. ). This experiment also found no evidence of restoration of O2 reactivity, even though there was several ML's worth of material sublimed during the highest TNP flash.