@article {2427,
	title = {Reactive uptake studies of NO3 and N2O5 on alkenoic acid, alkanoate, and polyalcohol substrates to probe nighttime aerosol chemistry},
	journal = {Physical Chemistry Chemical Physics},
	volume = {11},
	number = {36},
	year = {2009},
	note = {ISI Document Delivery No.: 491ADTimes Cited: 6Cited Reference Count: 86Gross, Simone Iannone, Richard Xiao, Song Bertram, Allan K.},
	pages = {7792-7803},
	type = {Article},
	abstract = {Heterogeneous reactions between NO3 and N2O5 and diethyl sebacate (DES), glycerol, oleic acid (OA), linoleic acid (LA), and conjugated linoleic acid (CLA) were studied to understand better nighttime aerosol chemistry. The reactive uptake coefficient of NO3 on the liquid alkenoic acids (OA, LA, and CLA) was found to be >0.07, which is higher than previous results for unsaturated organics, including alkenoic acids. This reaction could potentially be an important loss process of particle-phase unsaturated organic compounds in the atmosphere and in laboratory secondary organic aerosol studies. The reactive uptake coefficient of N2O5 on liquid glycerol was also found to be relatively large with a value of (3.2-8.5) x 10(-4), suggesting that N2O5 heterogeneous reactions with alcohols may also be atmospherically relevant. For all measurements with OA, CLA, and DES, the reactive uptake coefficients decreased significantly upon freezing. One possible explanation is that the liquid reaction is due to both a surface reaction and a bulk reaction and that the freezing process significantly decreases the importance of any bulk reactions. NO3 reactive uptake coefficients for liquid-phase compounds decreased in magnitude in the order: alkenoic acids > DES > glycerol. This is different compared to previous gas-phase studies and the difference may be due to the large viscosity of glycerol compared to the other organic compounds studied. N2O5 reactive uptake coefficients for liquid-phase compounds decreased in magnitude in the order: glycerol > LA > DES congruent to OA congruent to CLA.},
	keywords = {ATMOSPHERIC PARTICLES, CLOUD DROPLETS, DINITROGEN PENTOXIDE, GAS-PHASE DIFFUSION, HETEROGENEOUS OXIDATION, MIXED PARTICLES, OLEIC-ACID, RATE COEFFICIENT, SOLUBLE ORGANIC-COMPOUNDS, SULFURIC-ACID},
	isbn = {1463-9076},
	url = {<Go to ISI>://000269548300004},
	author = {Gross, S. and Iannone, R. and Xiao, S. and Bertram, A. K.}
}
@article {2431,
	title = {A study of oleic acid and 2,4-DHB acid aerosols using an IR-VUV-ITMS: insights into the strengths and weaknesses of the technique},
	journal = {Physical Chemistry Chemical Physics},
	volume = {11},
	number = {36},
	year = {2009},
	note = {ISI Document Delivery No.: 491ADTimes Cited: 3Cited Reference Count: 66Hanna, Sarah J. Campuzano-Jost, Pedro Simpson, Emily A. Burak, Itamar Blades, Michael W. Hepburn, John W. Bertram, Allan K.},
	pages = {7963-7975},
	type = {Article},
	abstract = {An investigation of oleic acid and 2,4-dihydroxybenzoic (DHB) acid aerosols was carried out using an aerosol mass spectrometer with pulsed lasers for vaporization and ionization and an ion trap for mass analysis. The extent of ion fragmentation was studied as a function of both vaporization energy and ionization wavelength. Low CO2 laser energies in the vaporization stage and near-threshold single photon ionization resulted in the least fragmented mass spectra. For DHB, only the molecular ion was observed, but for oleic acid fragmentation could not be eliminated. Tandem MS of the main fragment peak from oleic acid was carried out and provided a tool for compound identification. Photoionization efficiency curves were also collected for both DHB and oleic acid and the appearance energies of both parent and fragment ions were measured. Evidence for fragmentation occurring post-ionization is given by the similar appearance energies for both the parent and fragment ions. The results from this study were compared with those from similar experiments undertaken with time-of-flight (TOF) mass analyzers. The degree of fragmentation in the ion trap was considerably higher than that seen with TOF systems, particularly for oleic acid. This was attributed to the long storage interval in the ion trap which allows time for metastable ions to decay. Differences in the degree of fragmentation between the ion trap and TOF studies also provided further evidence for fragmentation occurring post-ionization. For 2,4-dihydroxybenzoic acid, the long delay prior to mass analysis also allowed time for reactions with background gases, in this case water, to occur.},
	keywords = {ATMOSPHERIC PARTICLES, CHEMICAL-ANALYSIS, ENVIRONMENTAL PARTICLES, GENERATING PARTICLE BEAMS, INVERSE FOURIER-TRANSFORM, LASER-DESORPTION/IONIZATION, ORGANIC-COMPOUNDS, QUADRUPOLE ION-TRAP, TRAP MASS-SPECTROMETER, VACUUM-ULTRAVIOLET PHOTOIONIZATION},
	isbn = {1463-9076},
	url = {<Go to ISI>://000269548300022},
	author = {Hanna, S. J. and Campuzano-Jost, P. and Simpson, E. A. and Burak, I. and Blades, M. W. and Hepburn, J. W. and Bertram, A. K.}
}
@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 {1157,
	title = {Reactive uptake of O-3 by multicomponent and multiphase mixtures containing oleic acid},
	journal = {Journal of Physical Chemistry A},
	volume = {109},
	number = {25},
	year = {2005},
	note = {ISI Document Delivery No.: 940CZTimes Cited: 55Cited Reference Count: 80},
	month = {Jun},
	pages = {5579-5589},
	type = {Article},
	abstract = {The heterogeneous reaction of O-3 with lauric acid/oleic acid (LA/OA) mixtures and myristic acid/oleic acid (MA/OA) mixtures were studied as a function of con position, physical state, and microstructure at 298 K. Lauric acid and myristic acid are both alkanoic acids whereas oleic acid is an alkenoic acid. Additionally, we investigated the uptake of O-3 by multicomponent mixtures that closely represent the composition of meat-cooking, aerosols. These measurements were performed with a rotating-wall flow-tube reactor coupled to a chemical ionization mass spectrometer. The reactive uptake coefficients (gamma) of O-3 on liquid LA/OA and MA/OA solutions range from 4 x 10(-4) to 7.2 x 10(-4) The gamma values measured for solid-liquid LA/OA and MA/OA mixtures (which consist of solid LA or solid MA. in equilibrium with a liquid) range from 2 x 10(-5) to 1.7 x 10(-4). These experiments show that only 79\% solid by mass in the solid-liquid mixture can decrease gamma by an order of magnitude compared to the liquid mixtures. The gamma values for solid-liquid mixtures that closely represent the composition of meat-cooking aerosols range from 1.6 x 10(-5) to 6.9 x 10(-5). We found that gamma of solid-liquid mixtures depends on the microstructure of the mixtures, which in turn depends on the method of preparing the films. Furthermore, experiments employing solid-liquid mixtures show an increase in gamma with increasing film age. This can be explained either by the formation of a nonequilibrium phase followed by its relaxation to the stable phase or by Ostwald{\textquoteright}s ripening, which refers to a change in the solid microstructure due to a tendency to minimize the total surface free energy of the solid. We used the obtained gamma values to estimate OA lifetimes for polluted atmospheric conditions. For liquid solutions, the lifetimes were on the order of a few minutes. The lifetimes derived for solid-liquid mixtures are up to 75 min, significantly longer than for liquid solutions. Our study emphasizes the effect of the physical state and microstructure of multicomponent mixtures on the heterogeneous chemistry.},
	keywords = {AIR-POLLUTION, ATMOSPHERIC PARTICLES, CLOUD MICROPHYSICS, FINE ORGANIC AEROSOL, HETEROGENEOUS REACTION, KINETICS, METAL-ALLOYS, ozone, PARTICULATE MATTER, UNSATURATED FATTY-ACIDS},
	isbn = {1089-5639},
	url = {<Go to ISI>://000230122600007},
	author = {Knopf, D. A. and Anthony, L. M. and Bertram, A. K.}
}
@article {957,
	title = {Deliquescence of malonic, succinic, glutaric, and adipic acid particles},
	journal = {Journal of Geophysical Research-Atmospheres},
	volume = {109},
	number = {D6},
	year = {2004},
	note = {ISI Document Delivery No.: 809FPTimes Cited: 32Cited Reference Count: 46},
	month = {Mar},
	pages = {8},
	type = {Article},
	abstract = {In order to understand and predict the role of organic particles in the atmosphere their deliquescence behavior must be understood. Using an optical microscope coupled to a flow cell, we investigated the deliquescence of malonic, succinic, glutaric, and adipic acid particles with sizes ranging from 2 to 40 mm. Deliquescence relative humidities were determined for temperatures ranging from 293 to 243 K. Over this temperature range both succinic acid and adipic acid deliquesced at approximately 100\% relative humidity, whereas malonic acid and glutaric acid deliquesced at significantly lower relative humidities. These results are generally in good agreement with previous studies and are within 3\% of calculations based on the UNIQUAC (universal quasi-chemical) Functional Group Activity Coefficients (UNIFAC) model and recently published interaction parameters. Our studies also include measurements at temperatures below the eutectic temperatures. At these temperatures, ice did not nucleate; rather the particles underwent deliquescence to form metastable solution droplets. This indicates that solid dicarboxylic acids are not good ice nuclei above 243 K and hence will probably not play a role in ice cloud formation at these temperatures.},
	keywords = {AEROSOL, AEROSOL PHASE, AMAZON BASIN, AMMONIUM-SULFATE, atmospheric chemistry, ATMOSPHERIC PARTICLES, CIRRUS CLOUD FORMATION, deliquescence, dicarboxylic acid, DICARBOXYLIC-ACIDS, HYGROSCOPIC GROWTH, ice, NUCLEATION, optical microscopy, PHASE-TRANSITIONS, STRATOSPHERIC TEMPERATURES, WATER},
	isbn = {0148-0227},
	url = {<Go to ISI>://000220622900002},
	author = {Parsons, M. T. and Mak, J. and Lipetz, S. R. and Bertram, A. K.}
}
