Interaction of hydrogen chloride with an ultrathin ice film. Observation of adsorbed and absorbed states

Journal Article · Thu Jun 09 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100074a026· OSTI ID:7267319

Graham, J D; Roberts, J T ^[1]

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1. Univ. of Minnesota, Minneapolis, MN (United States)

With the objective of gaining insight into how heterogeneous reactions occur in the Antarctic stratosphere, we have initiated a program to study the adsorption and reaction of simple molecules on model polar stratospheric cloud surfaces. In this work, the temperature-programmed desorption of hydrogen chloride from ultrathin (5-20 monolayers thick) water films is described. Two distinct HCl desorption states, designated [alpha]- and [beta]-HCl, are observed at 140 and 180 K, respectively. Water sublimation occurs at 180 K and is concurrent with [beta]-HCl evolution. [beta]-HCl, which is formed exclusively at low HCl exposures, is derived from the thin film bulk, while [alpha]-HCl is associated with an adsorbed state. [beta]-HCl is assigned to the sublimation of a stoichiometric phase of HCl and water, probably HCl-6H[sub 2]O, and [alpha]-HCl is assigned to the thermal desorption of HCl from the hexahydrate surface. Desorption spectra of HCl from ice-d[sub 2] show that H-D exchange between HCl and D[sub 2]O is much less than would be expected for a dissociatively adsorbed state of HCl. The [alpha] state is therefore assigned to molecularly adsorbed HCl. 38 refs., 11 figs.

• OSTI ID: 7267319
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:23; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540110
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ABSORPTION
ADSORPTION
ANTARCTIC REGIONS
ATMOSPHERIC CHEMISTRY
CHEMICAL ACTIVATION
CHEMISTRY
CHLORINE COMPOUNDS
CLOUDS
CRYOSPHERE
DESORPTION
EARTH ATMOSPHERE
ELEMENTS
EVAPORATION
FILMS
HALOGEN COMPOUNDS
HEAVY WATER
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
ICE
INORGANIC ACIDS
LAYERS
MASS SPECTROSCOPY
METALS
NICKEL
OXYGEN COMPOUNDS
OZONE LAYER
PHASE TRANSFORMATIONS
POLAR REGIONS
SORPTION
SPECTROSCOPY
STRATOSPHERE
SUBLIMATION
TRANSITION ELEMENTS
TUNGSTEN
WATER
X-RAY SPECTROSCOPY