In all the kinetics experiments reported below and in the SI, the trap was irradiated by both the 532 nm laser (at ~10 mW) and the CO2 laser at 5% duty factor (~0.5 W) during NP injection, pre-heating the NP briefly (< ~100 msec) prior to the start of the kinetics measurements. Because the CO2 laser peak power varies non-linearly with duty factor (the discharge rise time is slower than the "on" time at low duty factors), the max TNP reached during pre-heating is unclear, but we estimate that it would have been near 2000 K. This would desorb contaminants and transform the NPs to have Si-rich composition of at least their surface layers. Tmelt for amorphous SiO2 is ~1986 K compared to 1687 K for Si, thus pre-heating would have almost certainly melted the Si-rich surface layer, and possibly the entire NP.