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Uptake of Cl and Br by organic surfaces—A perspective on organic aerosols processing by tropospheric oxidants
Author(s) -
Moise Tamar,
Rudich Yi
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl013583
Subject(s) - alkene , alkane , troposphere , x ray photoelectron spectroscopy , sticking coefficient , analytical chemistry (journal) , chemistry , phase (matter) , contact angle , photochemistry , materials science , hydrocarbon , chemical engineering , environmental chemistry , organic chemistry , catalysis , adsorption , meteorology , physics , desorption , engineering , composite material
The reactive uptake of Cl and Br atoms by closely packed organic thin films was studied in a flow reactor. For Cl, the reactive uptake coefficient, γ, was near collision rate for alkane and alkene surfaces. For Br, γ =(3±1)×10 −2 for alkane and γ=(5±2)×10 −2 for alkene surfaces. The processing of the surface was monitored using FTIR, XPS and contact angle measurements. Oxidized surface‐bound products and a concurrent increase in hydrophilicity were observed. The probability of a reactive collision between Br, Cl, O(³P), O 3 and NO 3 and surface‐bound organics is compared with that of comparable gas‐phase reactions, showing that reactions with a high activation energy in the gas‐phase have an enhanced surface reaction probability. The uptake coefficients for these tropospheric oxidants are used to estimate the processing time for an organic coated aerosol.