TY  - JOUR
AU  - Röckmann, T.
AU  - Walter, S.
AU  - Bohn, B.
AU  - Spahn, H.
AU  - Brauers, T.
AU  - Tillmann, R.
AU  - Schlosser, E.
AU  - Koppmann, R.
AU  - Rohrer, F.
TI  - Isotope effect in the formation of H2 from H2CO studied at the atmospheric simulation chamber SAPHIR
JO  - Atmospheric chemistry and physics
VL  - 10
SN  - 1680-7316
CY  - Katlenburg-Lindau
PB  - EGU
M1  - PreJuSER-12234
SP  - 5343-5357
PY  - 2010
N1  - We thank Cornelia Richter for initial model studies to determine the most suitable conditions in the SAPHIR chamber. This work was funded by the Dutch science foundation NWO, project 816.01.001, H<INF>2</INF> budget.
AB  - Formaldehyde of known, near-natural isotopic composition was photolyzed in the SAPHIR atmosphere simulation chamber under ambient conditions. The isotopic composition of the product H-2 was used to determine the isotope effects in formaldehyde photolysis. The experiments are sensitive to the molecular photolysis channel, and the radical channel has only an indirect effect and cannot be effectively constrained. The molecular channel kinetic isotope effect KIEmol, the ratio of photolysis frequencies j(HCHO -> CO+H-2)/j(HCDO -> CO+HD) at surface pressure, is determined to be KIEmol = 1.63(-0.046)(+0.038) . This is similar to the kinetic isotope effect for the total removal of HCHO from a recent relative rate experiment (KIEtot= 1.58 +/- 0.03), which indicates that the KIEs in the molecular and radical photolysis channels at surface pressure (approximate to 100 kPa) may not be as different as described previously in the literature.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000279391100004
DO  - DOI:10.5194/acp-10-5343-2010
UR  - https://juser.fz-juelich.de/record/12234
ER  -