Open AccessFreezing behavior of single sulfuric acid aerosols suspended in a quadrupole trap
Author(s) -
Carleton K. L.,
Sonnenfroh D. M.,
Rawlins W. T.,
Wyslouzil B. E.,
Arnold S.
Publication year - 1997
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/97jd00009
Subject(s) - sulfuric acid , particle (ecology) , quadrupole , freezing point , materials science , analytical chemistry (journal) , slush , phase diagram , mineralogy , chemistry , chromatography , geology , phase (matter) , thermodynamics , atomic physics , metallurgy , oceanography , composite material , physics , organic chemistry
The freezing properties of sulfuric acid droplets were studied by suspending single 20‐ to 30‐μm‐diameter particles in a quadrupole trap and cooling them to stratospheric temperatures (≥191.5 K). Each particle's dc balance voltage was measured to determine the particle composition as a function of temperature and map out the particle's trajectory relative to the sulfuric acid phase diagram. Angularly resolved optical scattering patterns were monitored to detect freezing events. Particles cooled through the sulfuric acid tetrahydrate region (35–70 wt % H 2 SO 4 ) did not freeze and remained spherical liquid droplets for several hours. Only particles cooled through the ice‐liquid equilibrium region (<35 wt% H 2 SO 4 ) showed evidence of freezing. This supports previous experimental and field observations that stratospheric sulfuric acid aerosols are likely to remain liquid to within a few degrees of the ice frost point.