@article {1519,
	title = {Crystallization of aqueous inorganic-malonic acid particles: Nucleation rates, dependence on size, and dependence on the ammonium-to-sulfate},
	journal = {Journal of Physical Chemistry A},
	volume = {110},
	number = {26},
	year = {2006},
	note = {ISI Document Delivery No.: 058DRTimes Cited: 16Cited Reference Count: 63},
	month = {Jul},
	pages = {8108-8115},
	type = {Article},
	abstract = {Using an electrodynamic balance, we determined the relative humidity ( RH) at which aqueous inorganic-malonic acid particles crystallized, with ammonium sulfate ((NH4)(2)SO4), letovicite ((NH4)(3)H(SO4)(2)), or ammonium bisulfate (NH4HSO4) as the inorganic component. The results for (NH4)(2)SO4-malonic acid particles and (NH4)(3)H(SO4)(2)-malonic acid particles show that malonic acid decreases the crystallization RH of the inorganic particles by less than 7\% RH when the dry malonic acid mole fraction is less than 0.25. At a dry malonic acid mole fraction of about 0.5, the presence of malonic acid can decrease the crystallization RH of the inorganic particles by up to 35\% RH. For the NH4HSO4-malonic acid particles, the presence of malonic acid does not significantly modify the crystallization RH of the inorganic particles for the entire range of dry malonic acid mole fractions studied; in all cases, either the particles did not crystallize or the crystallization RH was close to 0\% RH. Size dependent measurements show that the crystallization RH of aqueous (NH4)(2)SO4 particles is not a strong function of particle volume. However, for aqueous (NH4)(2)SO4-malonic acid particles ( with dry malonic acid mole fraction) 0.36), the crystallization RH is a stronger function of particle volume, with the crystallization RH decreasing by 6 +/- 3\% RH when the particle volume decreases by an order of magnitude. To our knowledge, these are the first size dependent measurements of the crystallization RH of atmospherically relevant inorganic-organic particles. These results suggest that for certain organic mole fractions the particle size and observation time need to be considered when extrapolating laboratory crystallization results to atmospheric scenarios. For aqueous (NH4)(2)SO4 particles, the homogeneous nucleation rate data are a strong function of RH, but for aqueous (NH4)(2)SO4-malonic acid particles (with dry organic mole fraction = 0.36), the rates are not as dependent on RH. The homogeneous nucleation rates for aqueous (NH4)(2)SO4 particles were parametrized using classical nucleation theory, and from this analysis we determined that the interfacial surface tension between the crystalline ammonium sulfate critical nucleus and an aqueous ammonium sulfate solution is between 0.053 and 0.070 J m(-2).},
	keywords = {AEROSOL-PARTICLES, ATMOSPHERIC PARTICLES, BALANCE, ELECTRODYNAMIC, HETEROGENEOUS NUCLEATION, HYGROSCOPIC PROPERTIES, MIXTURES, ORGANIC-COMPOUNDS, PHASE-TRANSITIONS, RELATIVE-HUMIDITY, WATER-UPTAKE},
	isbn = {1089-5639},
	url = {<Go to ISI>://000238645600017},
	author = {Parsons, M. T. and Riffell, J. L. and Bertram, A. K.}
}
@article {956,
	title = {Deliquescence and crystallization of ammonium sulfate particles internally mixed with water-soluble organic compounds},
	journal = {Journal of Physical Chemistry A},
	volume = {108},
	number = {52},
	year = {2004},
	note = {ISI Document Delivery No.: 882FPTimes Cited: 38Cited Reference Count: 66},
	month = {Dec},
	pages = {11600-11608},
	type = {Article},
	abstract = {The deliquescence and crystallization of ammonium sulfate particles internally mixed with water-soluble organic material have been studied, restricted to an organic mass fraction of less than 0.6. The organic species used were malonic acid, glycerol, levoglucosan (1,6-anhydro-beta-D-glucopyranose), and Suwannee River fulvic acid. Our deliquescence results for systems with malonic acid and fulvic acid are in agreement with existing literature values. Glycerol deliquescence results are slightly lower than previous measurements. The levoglucosan results are the first of this kind. Total deliquescence relative humidities for the different systems are the same within the uncertainty of the measurements when the organic mole fraction is less than approximately 0.35. At an organic mole fraction of 0.6, the maximum deviation of total deliquescence relative humidities between the systems is approximately 10\% relative humidity. We show that thermodynamic calculations based on a simplified version of a model recently proposed by Clegg et al. (J. Aerosol Sci. 2001, 32, 713)1 are in agreement with measured values of deliquescence relative humidity up to an organic mole fraction of approximately 0.4 for most of the systems studied. The crystallization relative humidity (CRH) of mixed systems of ammonium sulfate with malonic acid, glycerol, or levoglucosan decreases significantly from the CRH of pure ammonium sulfate when the organic mole fraction is greater than about 0.25. This is in contrast to our previous study with glutaric acid where CRH remained close to CRH of pure ammonium sulfate up to a glutaric acid mole fraction of 0.4. CRH values are shown to vary depending on the type of,organic present. In terms of atmospheric implications, we estimate that organics, on average, are only a minor perturbation on the deliquescence relative humidity of the pure inorganic particles, whereas the organics, on average, may decrease the CRH of pure inorganic particles significantly and this effect depends on the type of organic material.},
	keywords = {ATMOSPHERIC AEROSOL, BLACK CARBON, DICARBOXYLIC-ACIDS, FINE AEROSOL, HUMIC-LIKE SUBSTANCES, HYGROSCOPIC PROPERTIES, MODEL, PHASE-TRANSITIONS, PHYSICAL, RELATIVE-HUMIDITY, STATE},
	isbn = {1089-5639},
	url = {<Go to ISI>://000225924800016},
	author = {Parsons, M. T. and Knopf, D. A. and Bertram, A. K.}
}
