Accurate, direct measurements of OH yields from gas-phase ozone-alkene reactions using an in situ LIF instrument

摘要: We present direct, pressure-dependent measurements of OH yields from gas-phase ozone-alkene reactions, using the Harvard HOx instrument to obtain sensitive, accurate, and precise concentrations. As in previous studies our laboratory, steady-state [OH] is measured by laser-induced fluorescence (LIF); here, accurate LIF calibration allows us absolute for first time. To calibrate original system, we measure ozone plus tetramethylethylene (TME) as a function pressure. The pressure dependence agrees with results, so yield are now comparable accuracy those indirect studies. Prompt, low-pressure agree well 1 atm over longer timescales, confirming that much arises decomposition stabilized carbonyl oxides. also explore ethene, isobutene, isoprene. Yields isobutene isoprene pressure-dependent, consistent formation substituted observe no + finding instead constant 14%, line most but contrast results another study.