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| Titel |
The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol |
| VerfasserIn |
V. Soonsin, A. A. Zardini, C. Marcolli, A. Zuend, U. K. Krieger |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 23 ; Nr. 10, no. 23 (2010-12-10), S.11753-11767 |
| Datensatznummer |
250008950
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| Publikation (Nr.) |
 copernicus.org/acp-10-11753-2010.pdf |
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| Zusammenfassung |
We present vapor pressure data of the C2 to C5
dicarboxylic acids deduced from measured evaporation rates of
single levitated particles as both, aqueous droplets and solid
crystals. The data of aqueous solution particles over a wide
concentration range allow us to directly calculate activities
of the dicarboxylic acids and comparison of these activities
with parameterizations reported in the literature. The data of
the pure liquid state acids, i.e. the dicarboxylic acids in
their supercooled melt state, exhibit no even-odd alternation
in vapor pressure, while the acids in the solid form do. This
observation is consistent with the known solubilities of the
acids and our measured vapor pressures of the supercooled
melt. Thus, the gas/particle partitioning of the different
dicarboxylic acids in the atmosphere depends strongly on the
physical state of the aerosol phase, the difference being
largest for the even acids.
Our results show also that, in general, measurements of vapor
pressures of solid dicarboxylic acids may be compromised by
the presence of polymorphic forms,
crystalline structures with a high defect number, and/or
solvent inclusions in the solid material, yielding a higher
vapor pressure than the one of the thermodynamically stable
crystalline form at the same temperature. |
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