Surface coverage of HCL on ice
- Univ. of Colorado, Boulder, CO (United States)
Understanding the interaction of hydrogen chloride (HCl) on ice is an important first step in unraveling the details of heterogeneous reactions on polar stratospheric clouds. Using Laser Induced Thermal Desorption (LITD) techniques with monolayer sensitivity we have measured the interaction of HCl with ice versus ice temperature, HCl partial pressure, and film thickness. Ice films were prepared by depositing water vapor onto a cooled Al{sub 2}O{sub 3} substrate. The water pressure was adjusted to maintain a constant ice film thickness. The ice was then exposed to HCl partial pressures ranging from 5 x 10{sup -8}-1 x 10{sup -6} Torr. HCl uptake by ice was monitored as a function of time using LITD and a doubly differentially pumped mass spectrometer. At temperatures below 150K, the LITD signals indicated that the ice film rapidly formed a HCl{sm_bullet}H{sub 2}O trihydrate film. Between 150K and 175K, the HCl:H{sub 2}O ratio changed continuously with no observed stable HCl{sm_bullet}6H{sub 2}O hexahydrate. For ice at stratospheric temperatures, HCl uptake was limited to {approx}1 monolayer in agreement with previous estimates of monolayer HCl uptake by stratospheric ice.
- OSTI ID:
- 370022
- Report Number(s):
- CONF-960376-; TRN: 96:003805-0071
- Resource Relation:
- Conference: Spring national meeting of the American Chemical Society (ACS), New Orleans, LA (United States), 24-28 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of 211th ACS national meeting; PB: 2284 p.
- Country of Publication:
- United States
- Language:
- English
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