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Temperature dependence of OH diffusion in air and He
Author(s) -
Liu Yong,
Ivanov Andrey V.,
Molina Mario J.
Publication year - 2009
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 - 10.1029/2008gl036170
Subject(s) - diffusion , atmospheric pressure , polar , atmosphere (unit) , ionization , atmospheric temperature range , thermodynamics , range (aeronautics) , materials science , analytical chemistry (journal) , chemistry , physics , meteorology , ion , chromatography , organic chemistry , astronomy , composite material
Although accurate knowledge of OH diffusion under atmospheric conditions is important, only one experimental study has been carried out at room temperature. Here, we report laboratory measurements of the OH diffusion coefficient in He and in a mixture of He and air over the range 218–318 K, using a temperature‐controlled flow tube coupled to a low‐pressure chemical ionization mass spectrometer. The results, which show a strong, almost square dependence of the diffusion coefficient on temperature in He and air, are consistent with predictions obtained from our theoretical calculations for diffusion of its polar diffusive analogue, H 2 O, using the 6–12 Lennard‐Jones potential model with the collision parameters of water. This supports our hypothesis that the diffusion of OH can be accurately represented in the atmosphere by water, its polar diffusive analogue.