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Crystallization and immersion freezing ability of oxalic and succinic acid in multicomponent aqueous organic aerosol particles
Author(s) -
Wagner Robert,
Höhler Kristina,
Möhler Ottmar,
Saathoff Harald,
Schnaiter Martin
Publication year - 2015
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 - 10.1002/2015gl063075
Subject(s) - oxalic acid , succinic acid , nucleation , crystallization , aqueous solution , ice nucleus , aerosol , supersaturation , ice crystals , chemistry , chemical engineering , materials science , saturation (graph theory) , homogeneous , mineralogy , inorganic chemistry , thermodynamics , organic chemistry , optics , mathematics , engineering , physics , combinatorics
This study reports on heterogeneous ice nucleation efficiency of immersed oxalic and succinic acid crystals in the temperature range from 245 to 215 K, as investigated with expansion cooling experiments using suspended particles. In contrast to previous laboratory work with emulsified solution droplets where the precipitation of solid inclusions required a preceding freezing/evaporation cycle, we show that immersed solids readily form by homogeneous crystallization within aqueous solution droplets of multicomponent organic mixtures, which have noneutonic compositions with an excess of oxalic or succinic acid. Whereas succinic acid crystals did not act as heterogeneous ice nuclei, immersion freezing by oxalic acid dihydrate crystals led to a reduction of the ice saturation ratio at freezing onset by 0.066–0.072 compared to homogeneous freezing, which is by a factor of 2 higher than previously reported laboratory data. These observations emphasize the importance of oxalic acid in heterogeneous ice nucleation.