Solving the discrepancy between the direct and relative-rate determinations of unimolecular reaction kinetics of dimethyl-substituted Criegee intermediate (CH3)2COO using a new photolytic precursor.We have performed direct kinetic measurements of the thermal unimolecular reaction of (CH3)2COO in the temperature range 243-340 K and pressure range 5-350 Torr using time-resolved UV-absorption spectroscopy.  The results show that the thermal unimolecular reaction is even more important main loss process of (CH3)2COO in the atmosphere than direct kinetic studies have suggested hitherto.  Probably more importantly, current measurements bring the direct and relative-rate measurements of thermal unimolecular reaction kinetics of (CH3)2COO into quantitative agreement.
THERM