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Reaction and desorption of HCl and HBr following collisions with supercooled sulfuric acid
Author(s) -
Behr Peter,
Morris John R.,
Antman Melissa D.,
Ringeisen Bradley R.,
Splan Jennifer R.,
Nathanson Gilbert M.
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 - 10.1029/2000gl012716
Subject(s) - sulfuric acid , desorption , chemistry , inorganic chemistry , hydrochloric acid , deuterium , adsorption , organic chemistry , physics , quantum mechanics
Gaseous HCl and HBr react with sulfuric acid at rates that depend strongly on acid concentration over a range of acidities typical of stratospheric aerosols. We monitor the competition between immediate desorption and H→D exchange after HCl and HBr thermalize upon collision with the surface of deuterated sulfuric acid: the exchange probabilities decrease from 0.7 to 0.1 (HCl) and 0.9 to 0.2 (HBr) as the acid concentration is increased from 55 to 70 wt% D 2 SO 4 at 213 K. These measurements imply that HCl and HBr desorb faster than they dissociate at higher acidities, impeding the formation of Cl − and Br − in more acidic aerosols. Residence time measurements of HCl molecules that do enter the acid, however, indicate that HCl is more soluble than expected at high sulfuric acid concentrations.