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Record Details

Record 8 of 3339
Spectroscopic studies of model polar stratospheric cloud films
Author and Affiliation:
Tolbert, Margaret A.(NASA Ames Research Center, Moffett Field, CA, United States)
Koehler, Birgit G.(NASA Ames Research Center, Moffett Field, CA, United States)
Middlebrook, Ann M.(Cooperative Inst. for Research in Environmental Sciences, Colorado Univ.)
Abstract: Fourier transform infrared (FTIR) spectroscopy has been used to study nitric-acid/ice films representative of type I polar stratospheric clouds (PSCs). These studies reveal that in addition to amorphous nitric acid/ice mixtures, there are three stable stoichiometric hydrates of nitric acid: nitric-acid monohydrate (NAM), dihydrate (NAD), and trihydrate (NAT). We also observe two distinct crystalline forms of the trihydrate, which we denote alpha- and beta-NAT. These two forms appear to differ in their concentration of crystalline defects, but not in their chemical composition. In addition to probing the composition of type I PSCs, we have also used FTIR spectroscopy to study the interaction of HCl with model PSC films. In this work we find that for HCl pressures in the range 10 exp -5 to 10 exp -7 Torr, HCl is taken up by ice at 155 K to form a thin layer of HCl.6H2O. At 193 K, the uptake of HCl by ice was consistent with less than or equal to monolayer coverage. Uptake of HCl by alpha and beta-NAT at 175 K was also consistent with less than or equal to monolayer coverage.
Publication Date: Jan 01, 1993
Document ID:
19930067509
(Acquired Dec 28, 1995)
Accession Number: 93A51506
Subject Category: GEOPHYSICS
Document Type: Conference Paper
Publication Information: In: Optical methods in atmospheric chemistry; Proceedings of the Meeting, Berlin, Germany, June 22-24, 1992 (A93-51501 22-35); p. 48-58.
Publisher Information: Society of Photo-Optical Instrumentation Engineers, Bellingham, WA, United States
Contract/Grant/Task Num: NSF ATM-92-96067; NAG2-760
Financial Sponsor: NASA; United States
Organization Source: NASA Ames Research Center; Moffett Field, CA, United States
Description: 11p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ATMOSPHERIC CHEMISTRY; ICE CLOUDS; INFRARED SPECTROSCOPY; SPECTROSCOPIC ANALYSIS; STRATOSPHERE; CHEMICAL COMPOSITION; FOURIER TRANSFORMATION; HYDROCHLORIC ACID; NITRIC ACID
Imprint And Other Notes: In: Optical methods in atmospheric chemistry; Proceedings of the Meeting, Berlin, Germany, June 22-24, 1992 (A93-51501 22-35), p. 48-58.
Availability Source: Other Sources
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