ICARUS Chamber Experiment: 2014 FIXCIT Study_20140114_ISOPRENE/CYCLOHEXANE_Ozone_No Seed_Isoprene + O3, low NO, dry, no seeds

Goals: Isolate ozone chemistry from OH chemistry (OHchem should read zero); investigate ozone-related interferences with OH instruments; explore product formation, and compare to 140106 ozonolysis experiment. Summary: This was as clean of an experiment as we could have hoped. Cyclohexane seemed to scavenge the OH well, as very low signals of OH+isop tracers were observed. GTHOS measured all milestones of the experiment, and observed much higher interference when isoprene was added. The reaction seemed well-mixed in the beginning, leading to less undesired chemistry. The expected ozonolysis products (like HMHP) were observed with CIMS, as well as 1 to 2 ug/m^3 of particles that nucleated. The MAC and MVK traces on the GC-FID appear to be free of interferences. At the end lights were turned on at 100% for 1 h. After lights off, seeds were added for 1 h. Formaldehyde LIF measured successfully today, which is great news. There seemed to be some interference on the GTHOS even though OH was scrubbed, although interferences may be lower than at the end of the HPALD experiment. Organization: 2014 FIXCIT Study Lab Affiliation: California Institute of Technology Chamber: Seinfeld chambers Experiment Category: Gas phase chemical reaction Oxidant: Ozone Reactants: ISOPRENE, CYCLOHEXANE Reaction Type: Photooxidation Relative Humidity: 5 Temperature: 25 Pressure: 750 Torr