@article {2064,
	title = {Ice nucleation on mineral dust particles: Onset conditions, nucleation rates and contact angles},
	journal = {Journal of Geophysical Research-Atmospheres},
	volume = {113},
	year = {2008},
	note = {ISI Document Delivery No.: 375WPTimes Cited: 16Cited Reference Count: 62Eastwood, Michael L. Cremel, Sebastien Gehrke, Clemens Girard, Eric Bertram, Allan K.},
	month = {Nov},
	pages = {9},
	type = {Article},
	abstract = {An optical microscope coupled to a flow cell was used to investigate the onset conditions for ice nucleation on five atmospherically relevant minerals at temperatures ranging from 233 to 246 K. Here we define the onset conditions as the humidity and temperature at which the first ice nucleation event was observed. Kaolinite and muscovite were found to be efficient ice nuclei in the deposition mode, requiring relative humidities with respect to ice (RHi) below 112\% in order to initiate ice crystal formation. Quartz and calcite, by contrast, were poor ice nuclei, requiring relative humidities close to water saturation before ice crystals would form. Montmorillonite particles were efficient ice nuclei at temperatures below 241 K but were poor ice nuclei at higher temperatures. In several cases, there was a lack of quantitative agreement between our data and previously published work. This can be explained by several factors including the mineral source, the particle sizes, the surface area available for nucleation, and observation time. Heterogeneous nucleation rates (J(het)) were calculated from the measurements of the onset conditions (temperature and RHi) required from ice nucleation. The Jhet values were then used to calculate contact angles (theta) between the mineral substrates and an ice embryo using classical nucleation theory. The contact angles measured for kaolinite and muscovite ranged from 6 degrees to 12 degrees, whereas for quartz and calcite, the contact angles ranged from 25 degrees to 27 degrees. The reported Jhet and q values may allow for a more direct comparison between laboratory studies and can be used when modeling ice cloud formation in the atmosphere.},
	keywords = {AFRICAN DUST, AMMONIUM-SULFATE PARTICLES, CIRRUS CLOUDS, CUBIC ICE, GENERATED LIQUID AEROSOLS, HETEROGENEOUS NUCLEATION, MICROPHYSICS, NUCLEI, SOOT, WATER},
	isbn = {0148-0227},
	url = {<Go to ISI>://000261144800007},
	author = {Eastwood, M. L. and Cremel, S. and Gehrke, C. and Girard, E. and Bertram, A. K.}
}
@article {1558,
	title = {Measurements of the vapor pressure of cubic ice and their implications for atmospheric ice clouds},
	journal = {Geophysical Research Letters},
	volume = {33},
	number = {17},
	year = {2006},
	note = {ISI Document Delivery No.: 081QHTimes Cited: 17Cited Reference Count: 38Shilling, J. E. Tolbert, M. A. Toon, O. B. Jensen, E. J. Murray, B. J. Bertram, A. K.},
	month = {Sep},
	pages = {5},
	type = {Article},
	abstract = {Under conditions commonly found in Earth{\textquoteright}s atmosphere, water can form two solid phases; hexagonal ice (I-h) and cubic ice (I-c). Recent reports have suggested that Ic may form in the atmosphere under a wider range of conditions than previously believed. In light of these reports, the formation of Ic has been suggested as one contributing factor for in-situ observations of persistent in-cloud supersaturations in cold cirrus. However, an accurate evaluation of the contribution of Ic formation to the observed supersaturations requires knowledge of the saturation vapor pressure of Ic, which has not been measured. In this manuscript, we report direct measurements of the vapor pressure of Ic over the temperature range 180 - 190 K. Over this temperature range, the vapor pressure of the cubic phase is 10.5 +/- 2.5\% higher than that of the hexagonal phase. Field measurements of in-cloud supersaturations made during CRYSTAL-FACE are also re-analyzed and discussed.},
	keywords = {AMORPHOUS WATER ICE, ASTROPHYSICAL IMPLICATIONS, CIRRUS CLOUDS, ELECTRON DIFFRACTION, FORMS, GLASSY, HEXAGONAL ICE, LOW-TEMPERATURE, SPECTRA, WATER, X-RAY-DIFFRACTION},
	isbn = {0094-8276},
	url = {<Go to ISI>://000240331600005},
	author = {Shilling, J. E. and Tolbert, M. A. and Toon, O. B. and Jensen, E. J. and Murray, B. J. and Bertram, A. K.}
}
