Deposition nucleation viewed as homogeneous or immersion freezing in pores and cavities

Marcolli, Claudia

doi:10.5194/acp-14-2071-2014

Cited by 251 publications

(338 citation statements)

References 179 publications

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“…The critical embryo radius calculated with CNT can be validated by testing its consistency with the melting and freezing point depression of ice observed in pores of mesoporous silica (Marcolli, 2014). When pores are too narrow to incorporate an ice crystal of critical size, ice will not nucleate.…”

Section: Classical Nucleation Theorymentioning

confidence: 99%

“…Subcritical ice clusters may be produced at a high rate but are prevented from reaching a critical size by the confinement in the pores. Marcolli (2014) showed that the CNT-based parameterization by Zobrist et al (2007) is able to describe the observed melting point depression in pores as a function of temperature and should therefore be well suited to estimate critical embryo sizes. The critical embryo volume for homogeneous ice nucleation predicted by this parameterization is 109 nm 3 at 254 K and increases to 1441 nm 3 at 265 K. We therefore consider the energy barrier and critical embryo size predicted by CNT as a quantity with a physical basis.…”

Section: Classical Nucleation Theorymentioning

confidence: 99%

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Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

et al. 2017

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Abstract. Homogeneous nucleation of ice in supercooled water droplets is a stochastic process. In its classical description, the growth of the ice phase requires the emergence of a critical embryo from random fluctuations of water molecules between the water bulk and ice-like clusters, which is associated with overcoming an energy barrier. For heterogeneous ice nucleation on ice-nucleating surfaces both stochastic and deterministic descriptions are in use. Deterministic (singular) descriptions are often favored because the temperature dependence of ice nucleation on a substrate usually dominates the stochastic time dependence, and the ease of representation facilitates the incorporation in climate models. Conversely, classical nucleation theory (CNT) describes heterogeneous ice nucleation as a stochastic process with a reduced energy barrier for the formation of a critical embryo in the presence of an ice-nucleating surface. The energy reduction is conveniently parameterized in terms of a contact angle α between the ice phase immersed in liquid water and the heterogeneous surface. This study investigates various ice-nucleating agents in immersion mode by subjecting them to repeated freezing cycles to elucidate and discriminate the time and temperature dependences of heterogeneous ice nucleation. Freezing rates determined from such refreeze experiments are presented for Hoggar Mountain dust, birch pollen washing water, Arizona test dust (ATD), and also nonadecanol coatings. For the analysis of the experimental data with CNT, we assumed the same active site to be always responsible for freezing. Three different CNT-based parameterizations were used to describe rate coefficients for heterogeneous ice nucleation as a function of temperature, all leading to very similar results: for Hoggar Mountain dust, ATD, and larger nonadecanol-coated water droplets, the experimentally determined increase in freezing rate with decreasing temperature is too shallow to be described properly by CNT using the contact angle α as the only fit parameter. Conversely, birch pollen washing water and small nonadecanol-coated water droplets show temperature dependencies of freezing rates steeper than predicted by all three CNT parameterizations. Good agreement of observations and calculations can be obtained when a pre-factor β is introduced to the rate coefficient as a second fit parameter. Thus, the following microphysical picture emerges: heterogeneous freezing occurs at ice-nucleating sites that need a minimum (critical) surface area to host embryos of critical size to grow into a crystal. Fits based on CNT suggest that the critical active site area is in the range of 10-50 nm 2 , with the exact value depending on sample, temperature, and CNT-based parameterization. Two fitting parameters are needed to characterize individual active sites. The contact angle α lowers the energy barrier that has to be overcome to form the critical embryo at the site compared to the homogeneous case where the critical embryo develops in the volume of water....

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Section: Classical Nucleation Theorymentioning

confidence: 99%

Section: Classical Nucleation Theorymentioning

confidence: 99%

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

et al. 2017

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“…5 are compared to modeled predictions of pore condensation and freezing (PCF) onsets. 66 Fig . 5 includes the calculated PCF freezing onsets for pore sizes in the ranges of 7.5-15 nm as the light brown colored area.…”

Section: Isothermal Ice Nucleation Experimentsmentioning

confidence: 99%

“…† Recently, it was proposed that deposition ice nucleation on mineral surfaces was likely a homogeneous or immersion freezing of water in pores or cavities. 66 Experimentally derived onset conditions shown in Fig. 5 are compared to modeled predictions of pore condensation and freezing (PCF) onsets.…”

Section: Isothermal Ice Nucleation Experimentsmentioning

confidence: 99%

Direct observation of ice nucleation events on individual atmospheric particles

Wang

Knopf

China

et al. 2016

Phys. Chem. Chem. Phys.

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The work presents microscopic observations of heterogeneous ice nucleation from experiments conducted inside an environmental scanning electron microscope. Observations of ice formation on kaolinite particles demonstrate that ice preferentially nucleates at the edges of the stacked platelets, rather than on the basal planes. This platform is applied for directly detecting and tracking ice nucleating particles in ambient aerosol samples and is complemented by micro-spectroscopic chemical imaging. This technique opens a path to new physical chemistry studies of ice formation in atmospheric science, cryobiology, and material science.www.rsc.org/pccp Heterogeneous ice nucleation is a physical chemistry process of critical relevance to a range of topics in the fundamental and applied sciences and technologies. Heterogeneous ice nucleation remains insufficiently understood, partially due to the lack of experimental methods capable of obtaining in situ microscopic details of ice formation over nucleating substrates or particles. We present microscopic observations of ice nucleation events on kaolinite particles at the nanoscale and demonstrate the capability of direct tracking and micro-spectroscopic characterization of individual ice nucleating particles (INPs) in an authentic atmospheric sample. This approach utilizes a custom-built ice nucleation cell, interfaced with an Environmental Scanning Electron Microscope (IN-ESEM platform) operated at temperatures and relative humidities relevant for heterogeneous ice nucleation. The IN-ESEM platform allows dynamic observations of individual ice formation events over particles in isobaric and isothermal experiments. Isothermal experiments on individual kaolinite particles demonstrate that ice crystals preferably nucleate at the edges of the stacked kaolinite platelets, rather than on their basal planes.These experimental observations of the location of ice nucleation provide direct information for further theoretical chemistry predictions of ice formation on kaolinite.

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“…Thus, these results suggest that different x therm or other approaches might be needed within different temperature regimes. Also, deposition nucleation close to water saturation may coincide with pore condensation freezing (Marcolli et al, 2014).…”

Section: Ice Nucleation Active Surface Site Densitiesmentioning

confidence: 99%

A new temperature- and humidity-dependent surface site density approach for deposition ice nucleation

et al. 2015

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Abstract. Deposition nucleation experiments with ArizonaTest Dust (ATD) as a surrogate for mineral dusts were conducted at the AIDA cloud chamber at temperatures between 220 and 250 K. The influence of the aerosol size distribution and the cooling rate on the ice nucleation efficiencies was investigated. Ice nucleation active surface site (INAS) densities were calculated to quantify the ice nucleation efficiency as a function of temperature, humidity and the aerosol surface area concentration. Additionally, a contact angle parameterization according to classical nucleation theory was fitted to the experimental data in order to relate the ice nucleation efficiencies to contact angle distributions. From this study it can be concluded that the INAS density formulation is a very useful tool to describe the temperature-and humidity-dependent ice nucleation efficiency of ATD particles.Deposition nucleation on ATD particles can be described by a temperature-and relative-humidity-dependent INAS density function n s (T , S ice ) withwhere the temperature-and saturation-dependent function x therm is defined aswith the saturation ratio with respect to ice S ice > 1 and within a temperature range between 226 and 250 K. For lower temperatures, x therm deviates from a linear behavior with temperature and relative humidity over ice.Also, two different approaches for describing the time dependence of deposition nucleation initiated by ATD particles are proposed. Box model estimates suggest that the timedependent contribution is only relevant for small cooling rates and low number fractions of ice-active particles.

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Deposition nucleation viewed as homogeneous or immersion freezing in pores and cavities

Cited by 251 publications

References 179 publications

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

Direct observation of ice nucleation events on individual atmospheric particles

A new temperature- and humidity-dependent surface site density approach for deposition ice nucleation

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