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Interaction of HCl with crystalline and amorphous ice: Implications for the mechanisms of ice‐catalyzed reactions
Author(s) -
Graham James D.,
Roberts Jeffrey T.
Publication year - 1995
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 - 10.1029/94gl03022
Subject(s) - amorphous ice , amorphous solid , adsorption , desorption , materials science , infrared spectroscopy , fourier transform infrared spectroscopy , chemical engineering , analytical chemistry (journal) , mineralogy , geology , crystallography , chemistry , organic chemistry , engineering
The interaction of HCl with ice under ultrahigh vacuum has been studied using temperature programmed desorption and single reflection Fourier transform infrared spectroscopy. Both amorphous and crystalline ice were investigated. At 120 K, HCl is initially absorbed by ice to form a stoichiometric hydrate phase identified as HCl · 6H 2 O. Upon completion of the bulk phase, HCl is adsorbed to the surface. This initial HCl adsorption probability on crystalline ice is ≈60% of that on amorphous ice. Furthermore, the adsorption probability on crystalline ice decreases more rapidly with increasing HCl uptake. As a result, HCl · 6H 2 O is more rapidly formed in amorphous ice. The difference in adsorption probabilities is tentatively attributed to a lower coverage of dangling OH groups at the crystalline ice surface.